Photo/Illutration A blue sky with light clouds is seen over Kokusai-dori, the main street in Naha, in June. (Tsukasa Kimura)

Travelers looking to avoid scorching summer heat in Japan may find a perfect, though unlikely, haven in the southernmost prefecture of Okinawa.

“Looking at only summer, there are very few extremely hot days. In a sense, I think (Okinawa Prefecture) can be called a 'summer retreat,'” said Chikara Yoshida, chief forecaster of the Japan Meteorological Agency’s Fukuoka Regional Headquarters. 

As Japan’s mainland battles through record heat this summer, with temperatures reaching around 40 degrees in many places, Okinawa Prefecture rarely sees the mercury hit 35 degrees.

As of Aug. 22, the highest temperature in the city of Fukuoka this year was 36.9 degrees recorded on Aug. 2.

In Fukuoka Prefecture, 37.9 degrees was the highest, observed in Kurume on July 1.

But Naha saw highs of 33.6 degrees in July and 33.5 degrees in August. There have been no days with the mercury reaching 35 degrees or higher this year.

“Okinawa is surrounded by the sea,” Yoshida said, meaning Okinawa Prefecture is always subject to an ocean breeze.

Yoshida said ocean water does not easily warm or cool, meaning the islands’ temperatures rarely reach extreme highs. 

Since mountains in the prefecture rise up to only about 500 meters above sea level, the islands are not easily affected by the Foehn effect, in which winds blowing down from mountains push up temperatures.

The average temperature in August over three decades until 2020 was higher in Naha, at 29.0 degrees, than in Fukuoka, at 28.4 degrees, and Tokyo, at 26.9 degrees, according to data compiled by the JMA.

However, Naha had 0.2 day with temperatures reaching 35 degrees or higher per year, while Tokyo had 4.8 days and Fukuoka had 8.1 days, the data showed. 

Okinawa only saw five days in the past when the temperature reached 36 degrees or higher, according to the JMA’s Okinawa Regional Headquarters.

One of those days was recorded in Ishigaki in 2012, at 36.1 degrees.