https://twitter.com/KiryeNet/status/1127924824674906113
In Naha, Okinawa Prefecture, the mean annual temperature for 2018 was 23.5℃.
Naha has had a little bit of cooling trend from 1998 to 2018.
https://www.data.jma.go.jp/obd/stats/etrn/view/monthly_s3_en.php?block_no=47936&view=1