An unexpected summer retreat? Amami Oshima – Comparing it to Tokyo and Osaka reveals its true potential as an island where you can escape the heatwave.

When you hear the name "Amami Oshima," many people probably picture a deep blue sea, strong sunshine, and the heat of a tropical paradise.

However, if you compare data from the Japan Meteorological Agency, you'll find that Amami in the summer is actually less prone to "dangerous heat" than Tokyo or Osaka. This time, we'll explain why Amami is a "hidden summer resort" based on temperature data from July to September.

Let's start by comparing the numbers! Temperature data from July to September.

Based on the Japan Meteorological Agency's average values (statistical period 1991-2020), we compared the temperatures in Amami (Naze), Tokyo, and Osaka.

[July]

	Average temperature	Highest temperature	Minimum temperature	average humidity
Amami (Naze)	28.8℃	32.3℃	26.0℃	77%
Tokyo	25.7℃	29.9℃	22.4℃	76%
Osaka	27.7℃	31.8℃	24.6℃	70%

[August]

	Average temperature	Highest temperature	Minimum temperature	average humidity
Amami (Naze)	28.5℃	32.0℃	26.0℃	78%
Tokyo	26.9℃	31.3℃	23.5℃	74%
Osaka	29.0℃	33.7℃	25.8℃	66%

[September]

	Average temperature	Highest temperature	Minimum temperature	average humidity
Amami (Naze)	27.0℃	30.4℃	24.3℃	78%
Tokyo	23.3℃	27.5℃	20.3℃	75%
Osaka	25.2℃	29.5℃	21.9℃	67%

When you compare them side by side like this, you'll find that Amami actually has the highest average temperature.

You might be thinking, "Hey, it's not cool at all!" But here's the main point.

The difference in the "quality of heat" in Amami that cannot be seen by numbers alone.

① There are almost no "extremely hot days (35℃ or higher)".

In Amami, the maximum temperature remains stable at around 30-32°C throughout July to September, with very few "extremely hot days" exceeding 35°C. On the other hand, Tokyo and Osaka are prime examples of cities where the number of extremely hot days has increased sharply in recent years. The difference is clearly visible when comparing the annual number of extremely hot days based on observation data from the Japan Meteorological Agency (average from 1991 to 2020).

	Extremely hot day
Amami (Naze)	A few days
Tokyo	Approximately 5.4 days
Osaka	Approximately 14.5 days

*The data for Tokyo and Osaka are based on annual averages derived from Japan Meteorological Agency observation data (1991-2020). Since Naze is not included in the aggregation of the 56 major weather stations, we have referred to the description in Amami Tourism's official information that "there are only a few days of extreme heat."

While Osaka experiences scorching hot days for about two weeks a year, Amami, surrounded by the sea, is less prone to sudden increases in air temperature due to the surrounding seawater temperature acting as a buffer. As a result, it rarely experiences the extreme heat approaching 40°C seen in inland areas and urban areas.

② Unaffected by the urban heat island effect

In large cities like Tokyo and Osaka, temperatures are gradually rising due to the " heat island effect ," where asphalt and buildings trap heat. According to observations by the Japan Meteorological Agency, the average temperature in Tokyo has risen by more than 3°C in the last 100 years, and this is largely attributed to the effects of urbanization.

Amami lacks these urban-specific "heat traps," and the natural topography and sea breeze directly reflect the temperature, making it less likely to feel the "stifling heat" that some people experience.

③ Sea breeze and shade, no need for air conditioning.

While the humidity levels in Amami are numerically slightly higher, the actual heat you feel when walking outside isn't determined solely by humidity. In Amami, sea breezes blow through even during the day, and subtropical trees provide dense shade. The feeling is completely different from the "damp heat" of Tokyo and Osaka, which are concrete jungles with strong reflected sunlight.

In other words, Amami is "a tropical paradise in terms of numbers, but feels like a summer resort."

summary

・Average temperatures can sometimes be higher than in Tokyo and Osaka.

However, the number of days with "dangerous heat" (extreme heat) is significantly lower.

- Because there is no heat island effect, it tends to feel cooler at night.

- The sea breeze and shade of the trees make the temperature feel milder even at the same temperature.

This is why Amami is called an "unexpected summer resort." For city dwellers who are tired of news reports of temperatures exceeding 35°C every day, here's why I recommend Amami in the summer.

How to enjoy Amami in the summer in a cooler way

Early morning and evening beach activities: The best time to enjoy the sea is when the sunlight is milder and the sea breeze is pleasant.

Canoeing in a mangrove forest: The shade of the trees and the water's edge will significantly lower your perceived temperature.

Pay close attention to typhoon season: Typhoons are likely to approach from July to October, so be sure to check the weather forecast before you travel.

奄美の海

*Temperature data is based on the Japan Meteorological Agency's "Normal Values (1991-2020)".