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Daikin 20th Survey on Attitudes of Modern People toward Air
"Investigation of the Summer in Tokyo!"

Awareness Survey of 100 Foreign Nationals Residing in Tokyo on "Summer Heat in Tokyo"

How Do Foreign Nationals Feel about Summer in Tokyo?
90% Say Hotter Than Home countries.

18 July 2014

Daikin Industries, Ltd. surveyed 100 foreign nationals currently residing in Tokyo on the theme of the "summer heat in Tokyo" in a questionnaire titled "The 20th Survey on Attitudes of Modern People toward Air."

The "Survey on Attitudes of Modern People toward Air" has been conducted since 2002 to understand the awareness of "air" among modern people and related issues as well as promote interest and appreciation in many people concerning "air," which are often taken for granted.

Because Tokyo was chosen as the host city of the 2020 Summer Olympic Games, a growing interest in Tokyo is expected worldwide accompanied by an increasing number of tourists. One of the biggest interests among overseas tourists is the Tokyo summer heat and its high humidity. In fact, the records for the number of days on which the temperature goes above 30℃ (86℉) and 35℃ (95℉) have repeatedly been broken one after another not only in Tokyo but also all over Japan. The average temperature in Tokyo has increased by at least 3℃ in the last 100 years, and Tokyo is said to be prominent among capitals of the world for its heat island phenomenon. This led us to investigate how people from overseas who are visiting Tokyo feel about the summer heat in Japan, in what they are interested, and what surprises them.

In this year's survey, which marks the 20th year of conducted surveys, Daikin investigated "awareness of and current status regarding the summer heat in Tokyo" among foreign nationals who have experienced the summer heat in Tokyo. The results showed that 90% of the respondents felt that "the summer in Tokyo is hotter than those experienced in their home countries." Moreover, the survey yielded an interesting result. While the respondents were surprised by the summer lifestyle of Japanese people who have adapted themselves well to the summer heat and the number of air conditioners installed in urban areas, they found themselves gradually and successfully adapting to the Japanese summer.

This survey report not only includes the observations of Daikin as an air conditioning manufacturer, but also introduces a description of summers in Tokyo and ideas on how to spend the summer comfortably in Tokyo by Ryoko Imamura, a certified weather forecaster.

The primary results of this survey are as follows:

Most people feel the heat is unbearable.
What is the summer heat in Tokyo and what are its characteristics?

  • Is the summer in Tokyo the harshest in the world? 90% say hotter than home countries.
  • Is the humidity the reason why it feels so hot? Are the temperatures of by asphalt- and concrete- covered ground, and the sultry nights the reasons why it feels so hot?
  • Japanese countermeasures for the heat that surprised foreign nationals: First was "Parasols" and second was "Paper and folding fans."
  • Japan is different! What scenes surprised them regarding the summer in Tokyo?
    - Does how you feel change depending on where you are? Interesting expressions in the world regarding the heat
  • Are foreign nationals more sensitive to the heat than Japanese? They set their AC at 24℃.
  • One in two foreign nationals is not confident in his or her ability to watch the Tokyo Olympic Games outdoors.
    - Services desired in the Olympic venues and cities
    - Advice on countermeasures for the heat from those who have experienced the summer in Tokyo to Olympians and spectators/tourists from the same country.

Is the summer in Tokyo the harshest in the world?
Approximately 90% responded that Tokyo is hotter than their home countries.

The average temperature in Tokyo has increased by at least 3℃ in the last 100 years, and Tokyo is said to be prominent among capitals of the world for its heat island phenomenon*. Based on the increasing numbers of extremely hot days on which the highest temperature goes above 35℃ and sultry nights when the temperature does not fall below 25℃, it is probably safe to say that the summer in Tokyo may be among one of the harshest in the world.

Now, how do people from overseas feel about the summer in Tokyo? We asked foreign nationals who have spent a summer in Tokyo: "How do you feel about the summer in Tokyo?" The results showed that all the respondents felt "The summer in Tokyo is hot." When they were asked how they feel about summers in Tokyo in comparison to those in their home countries, 25% stated "Unbearably hotter," 44% "Hotter," and 19% "Somewhat hotter," resulting in approximately 90% (88%) responding that "Tokyo is hotter than my home country."

Despite the fact that there are a number of cities in the Middle East, Southeast Asia, and Africa that are hotter than Tokyo when looking only at the temperature, many foreign nationals felt summers in Tokyo are hotter than those in their native countries.

Chart 1. How does summer in Tokyo compare with that in your country?

Heat island phenomenon: A phenomenon where the air temperature of urban areas becomes higher than the surrounding suburban areas. In urban areas, the temperature tends to increase markedly during the summer due to, among other things, the radiant heat from asphalt and buildings as well as the exhaust heat from cars and air conditioners. An increase in the daytime temperature as well as an increase in the number of sultry nights causes health hazards such as heat stroke and increased discomfort in daily life. In the last 100 years, the average temperature in Tokyo increased by at least 3℃, while the average increase in the temperature elsewhere was smaller than that in Tokyo: approximately 1.1℃ for the rest of Japan, approximately 0.6℃ worldwide, and approximately 1.6℃ in New York, to name a few.

Is humidity the reason why it feels so hot?
Are the temperatures of the asphalt- and concrete-covered ground and the sultry nights the reasons it feels so hot?

Why do people feel the summer in Tokyo is so hot? When the respondents were asked, "What do you think are the reasons why you feel the summer in Tokyo is so hot?" the overwhelming majority of the respondents stated "Because of the high humidity (by 80%)." It clearly points out the characteristics of the Japanese climate in which not only the temperature but also the humidity goes up during the summer due to the humid air blown in from the Pacific Ocean.

It was followed by "Because of the high temperature (by 56%)," "Because much of the ground is covered by asphalt and concrete (by 28%)," and "Because the temperature does not fall even during the night (by 28%)." These results correspond with the characteristics of the heat island phenomenon. Urbanization brought not only an increase in temperatures because of radiant heat from the ground being covered by asphalt and concrete, but also an increase in nighttime temperatures that do not fall easily because of the insufficient release of heat absorbed by the ground and buildings, all of which are conceivably the reasons why many foreign nationals feel Tokyo is so hot.

Chart 2. Why do you feel that summer (outdoors) in Tokyo is hot?

As the humidity increases, the sensible temperature of humans increases, causing them to feel hotter. There is an index called the "temperature - humidity index* " that quantitatively measures summer heat and humidity. This index is calculated based on temperature and humidity, and Tokyo is presumed to have a considerably high temperature-humidity index compared to other major cities in the world because of its high humidity during the summer.

Chart 3. temperature-humidity index of major cities.

  • * The definition of the temperature - humidity index: "-55: Cold"; "55-60: Chilly"; "60-65: Feel nothing"; "65-70: Comfortable"; "70-75: Not hot"; "75-80: Somewhat hot"; "80-85: Hot and sweaty"; "85-: Unbearably hot"

By the region from where the respondents come, those from the Middle East and Africa seem to have particular difficulty coping with the humidity (96% gave a response of "Because of the high humidity"). Meanwhile, many of those from Europe were shown to feel the heat because of the fact that the nighttime temperature stays hot (56% gave a response of "Because the temperature does not fall even during the night"). If looking at the temperature alone, there are other cities with a similar environment to Tokyo. However, the summer in Tokyo can be said to be among one of the harshest in the world as Tokyo has more than one factor that contributes to why a person feels hot.

Chart 4. (By region) Why do you feel that summer (outdoors) in Tokyo is hot?

Characteristics of the Summer in Tokyo (1)
By certified weather forecaster Ryoko Imamura

The average temperature in Tokyo has increased by approximately 3℃ in the last 100 years, partly due to the heat island phenomenon.

Because of the high humidity in addition to the high temperature, the sensible temperature of humans is higher than the actual temperature.

Moreover, the summer in Tokyo is characterized by the high nighttime temperature that does not fall easily. During the daytime, the concrete and asphalt absorb the solar radiation as well as the exhaust heat generated as a result of social activities (which is said to be equivalent to roughly 10% of the summer solar radiation), and the absorbed heat is released at night. However, the heat released from the concrete and asphalt is reabsorbed by buildings, preventing the heat from being released effectively and making the temperature fall into a vicious cycle of hardly dropping at all.

As a result, the temperature stays hot even during the night as evidenced last year (2013) by the days on which the lowest temperature exceeds 30℃. The fact that there is no time in the day when one can feel free from the heat is probably the reason why people from overseas feel "the summer in Tokyo is hotter than in their home countries."

Moreover, even in the same Tokyo, the inland area tends to get hotter than the coastal area. In general, it is more difficult for the temperature to increase on the sea than it is on the ground so it is more difficult for the temperature to increase in the coastal area where sea breezes blow than it is in the inland area.

Very high temperatures are recorded in some of the cities in the Kanto region, such as Kumagaya City in Saitama Prefecture, and this is partly due to the fact that the air warmed by the heat island phenomenon in the Tokyo metropolitan area is blown to Kumagaya City by the winds from the seaside.

For the same reason, the highest temperature in the Tokyo metropolitan area is often recorded around Nerima ward.









    tv asahi "Super J Channel" certified weather forecaster Ryoko Imamura

The Japanese countermeasure for the heat that most surprised foreign nationals was the "Use of parasols"

When the respondents were asked whether there are any countermeasures for the summer heat in Tokyo that impressed or surprised them, the most frequently cited response was the "Using parasols (by 46%)." Many Japanese women use parasols as a measure for the heat and preventing sunburn, but the results suggest that it is not a very common practice overseas as nearly half the respondents said they were surprised by the use of parasols.

The second most commonly cited response was the "Using paper fans (by 37%)," and the third most commonly cited response was "Wearing yukata (light summer kimono) (by 35%)" and " Using various products or goods to keep cool (by 35%)." These were followed by "Sprinkling water on streets (by 32%)" and "Hanging up wind chimes (by 32%)." These results indicate that foreign nationals are surprised by the various ideas and ways that Japanese people have traditionally utilized to beat the heat. In other words, what seems perfectly natural to Japanese people to keep cool appears strange when seen from the perspective of foreign nationals.

Chart 5. Do you see any ways people in Tokyo beat the summer heat that surprised or interested you?

While Japanese traditional ways to beat the heat ranked highly, there are also unexpectedly many foreign nationals who are surprised by the "Using air conditioners (by 18%)." Overseas residents seem surprised by the "use of air conditioners everywhere" in Japan, not only inside buildings but also inside vehicles, including electric trains. Some of the respondents also stated that they "feel cold indoors because the air conditioners are set at a temperature that is too low."

Japan is different!
What surprised foreign nationals regarding the summer in Tokyo?

When the respondents were asked, "Have you ever seen anything that impressed or surprised you during the summer in Tokyo?" many stated that they were surprised to see "Japanese businessmen working in suits without taking off their jackets despite the midsummer heat." Meanwhile, some stated that they got a strong impression from the fact that "despite the heat, people wear long gloves that go up to their upper arms or long sleeves as a sunburn prevention measure." With regard to products that give off a feeling of coolness, some were also surprised by seeing something unusual, even in the eyes of Japanese, such as "a person wearing a cap with an electric fan."

Things they saw in Tokyo that impressed or surprised them: Primary responses

  • Businessmen wearing ties and jackets. (A 21-year-old respondent from India)
  • As a sunburn prevention measure, women cover their arms with black covers (gloves) even during the summer. (A 47-year-old respondent from the U.S.)
  • A display of fireworks in and around the metropolitan area. Summer events such as the Tanabata Matsuri (star festival) and the Awa Odori dance festival. (A 28-year-old respondent from Hong Kong)
  • Paper fans are distributed free of charge. (A 33-year-old respondent from Thailand)
  • Despite the heat, work is always prioritized without changing the work hours. (A 41-year-old respondent from Morocco)
  • The soles of my shoes completely melted and were gone. (A 28-year-old respondent from Estonia)
  • I am amazed that I am surviving the summer (in Tokyo). (A 31-year-old respondent from France)

Does the way one feels about the heat change depending on where he or she is? Interesting expressions in the world regarding the heat

When the respondents were asked, "In your language, are there any unique expressions that describe the heat?" the following expressions were obtained. We can see there are various ways to describe or express the heat depending on the region, language, and culture.

Unique expressions of the heat: Primary responses

  • Hotter than Hades. (U.S.)
  • So hot that you can fry an egg on the ground. (U.S.)
  • A sparrow falls off the roof due to the heat (Netherlands)
  • Hot like a steaming pot (South Korea)
  • Unbearably hot like being grilled on a fire/Hot as if I were going to melt (Taiwan)
  • Hot like being in a steaming basket (Hong Kong)
  • Hot like my liver is bursting (Thailand)
  • I am sweating like a pig (Czech Republic)
  • Hot like being in an oven (Russia)

Are foreign nationals more sensitive to the heat than Japanese?
They set the air conditioner at 24℃.

Are there any differences in air conditioner use between Japanese and foreign nationals? When the respondents were asked, "Do you use an air conditioner at home in your country and in Japan?" 56% stated that they "use (an air conditioner) at home in their home countries" and 87% stated they "use (an air conditioner) at home in Japan." The results showed that many respondents, particularly those from European countries, tend not to use an air conditioner at home in their home countries and started using one for the first time after they came to Japan.

Chart 6. Do you use an air conditioner in your residence in your home country in the summer?
Chart 7. Do you use an air conditioner in your residence in Japan in the summer?

With regard to set temperature, the results showed that "The majority of foreign nationals set their air conditioners at 24℃."

The Japanese government promotes 28℃ as the recommended set temperature for air conditioners during the summer, but foreign nationals were shown to set their air conditioners at temperatures much lower than recommended. They tend to set their air conditioners at a temperature as low as possible, probably to survive the harsh summer heat in Tokyo.

In a hot and humid environment like Japan, it is particularly important to control the humidity to keep the indoor air comfortable. It is possible to feel cooler without lowering the set temperature of the air conditioner, such as by reducing the humidity via dehumidification or creating air currents using electric fans and the like.

Chart 8. If you use an air conditioner in Japan in your residence during the summer, what is the average temperature you set it at?

When looking at the current use of air conditioners according to the region from which the respondents come, "72% of those from Europe stated they have never used an air conditioner (until they came to Japan)." Meanwhile, the results showed that "the percentage of those who have never used an air conditioner decreased to 4% when they were asked about the use of air conditioners in Japan." Many of the respondents from European countries spend the summer without using an air conditioner because many areas in Europe have a relatively cool summer. However, even those who have never used an air conditioner seem unable to spend the summer in Tokyo without one.

Among the respondents who are from the Middle East or Africa, 52% stated they use ("Use frequently" + "Use sometimes") air conditioners in their home countries. However, this percentage increased to 100% after they came to Japan. As 96% of those from the Middle East and Africa cited "high humidity" as the reason why they feel the summer in Tokyo is so hot, air conditioners are probably indispensable for them to cope with the heat and humidity of Tokyo.

Chart 9. (By region) Do you use an air conditioner in your residence in your home country in the summer?

Chart 10. (By region) Do you use an air conditioner in your residence in Japan in the summer?

One in two foreign nationals is not confident in his or her ability to watch the Tokyo Olympic Games outdoors.

The Tokyo Olympic Games will be held in 2020 (scheduled from July 24 to August 9). The interest in Tokyo will undoubtedly increase for the next six years until the summer Olympics. Since it is an event held in midsummer, we asked the respondents if they would be confident in their ability to watch outdoor sports played in the middle of summer while withstanding the heat in Tokyo, and 54% responded "No (I would not be confident)." As was expected, those who have experienced the harsh summer in Tokyo seem to have difficulty being fully confident in their ability to watch games while enduring the summer heat.

Services desired in the Olympic venues and cities to beat the heat

As Tokyo represents a severe environment to watch games played outdoors, we asked the respondents if they could think of any services desired for the venues and cities to beat the heat. Many cited services such as "Areas in which one can avoid the direct sun or rest areas such as those with fountains," "Areas in which one can feel cool," and "Distribution of cold drinks and products that cool a person off."

Primary responses

  • Air-conditioned spectators' stands; large-sized fans for outdoor use that can create air currents
  • Misting systems to cool the air; public water fountains
  • Provision of ice cream and shaved ice
  • Vending machines for paper fans and caps
  • Shaded areas; sunglasses; women's clothes made of cool materials unique to Japan in western sizes
    ("I am female but my size is a men's XL in Japan. I would to find the bigger sizes in women's clothing.")

Advice on countermeasures for the heat from those who have experienced the summer in Tokyo to Olympians and spectators/tourists from the same country

We asked the respondents if they have any advice on countermeasures for the heat to Olympians and spectators/tourists as someone who has experienced spending a summer in Tokyo. They most frequently cited advice related to sufficient hydration, such as "Constantly drink water even if you are not thirsty" and "Take drinks with you as much as possible."

The advice given seemed to be based on their own experience, as there were quite a few respondents who suffered from heat stroke and dehydration during a summer in Tokyo.

There were also those who gave advice regarding what Japanese often do to beat the heat, such as using parasols and products that give off a feeling of coolness, probably because they learned from and have adapted the Japanese unique ways of coping with the heat of Japanese summers. With regard to countermeasures for the heat, they seem to have adapted themselves well to Japanese culture and successfully overcome the Japanese summer.

Because of the high humidity during summer in Tokyo, there are times when we sweat more than we think we do. This unfamiliar environment that differs from one's home country often leads to people becoming ill. Therefore, it is extremely important to constantly stay hydrated and rest in a cool area when the temperature is high. We hope you will be able to enjoy the summer in Tokyo by taking care of your physical condition.

Characteristics of the Summer in Tokyo (2)
By certified weather forecaster Ryoko Imamura

The weather forecast in Japan is highly accurate and provides detailed information compared to the rest of the world.

In recent years, there are an increasing number of short localized downpours in Tokyo called "guerrilla rainstorms," which are caused by a sudden warming of the air and partly due to the heat island phenomenon. However, many appropriate measures are being provided to cope with such abnormal weather. When you go out, it is advisable that you check the weather forecast for the region where you live and also for the region where you are going for the day in order to take the appropriate precautions.

Moreover, there are data indicating that the incidence of heat stroke increases the day after a sultry night and the lack of sleep gradually has a negative impact on one's health. Even when staying indoors, it is recommended to sufficiently take care of one's physical condition by controlling the room temperature with the use of air conditioners and similar.

Study Outline

Title: "Investigation of the Summer in Tokyo!" Awareness Survey on "Summer Heat in Tokyo"
Sponsored by: Daikin Industries, Ltd.
Conducted by: Macromill, Inc.
Method: Questionnaire survey (Internet Survey)
Survey period: June 13 (Fri.) to June 27 (Fri.), 2014
Respondents: Foreign nationals residing in Tokyo at least one year
Sample size: 100 samples *The breakdown is as per the following table.
Region United States/
Canada
Europe Asia Middle East/
Africa
Total
Respondents 25 25 25 25 100
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