Okinawa Climate
Compared to mainland Japan, Okinawa has a warm climate throughout the year.
During the daytime, strong sunlight shines down and UV exposure is quite high.
However, surprisingly, Okinawa’s annual sunshine duration is actually relatively short compared to other regions in Japan, meaning it is not always blue skies and sunshine year-round.
In this article, we take a closer look at Okinawa’s sunshine hours.
We also introduce recommended items for UV protection and sun care in Okinawa, so we hope this helps you plan your trip!
Sunshine Duration in Okinawa
From early June, when the rainy season ends, through around October, Okinawa experiences relatively long sunshine hours, with July being the sunniest month of the year.
From around December to March, however, cloudy and rainy days are more common, and January to February in particular have the shortest sunshine duration.
While Okinawa is often imagined as a place of constant sunshine, its actual daylight and sunshine hours vary significantly by season.
Okinawa is also classified as a subtropical oceanic climate, characterized by high temperatures and high humidity.
Surrounded by warm ocean waters, weather systems and rain clouds form easily, so it’s not unusual for the weather to suddenly change—even from clear skies to rain within just a few minutes.
Annual Sunshine Hours in Okinawa
According to data from the Japan Meteorological Agency (reference period: 1991–2020), Okinawa’s annual sunshine duration is 1,727 hours, ranking 36th in Japan.
For reference, the top three prefectures with the highest sunshine hours are:
1st: Yamanashi Prefecture – 2,226 hours
2nd: Kochi Prefecture – 2,159 hours
3rd: Gunma Prefecture – 2,153 hours
The national average is 1,916 hours, meaning Okinawa actually has fewer sunshine hours than the national average—an unexpected result for many.
However, this does not mean Okinawa is consistently cloudy throughout the year. Rather, there is a large seasonal variation between summer and winter, which leads to this overall ranking.
Next, let’s take a closer look at Okinawa’s monthly sunshine hours.
For easier comparison, we have also compared Okinawa’s annual sunshine hours with Yamanashi Prefecture, which ranks first in Japan.
▼Annual Sunshine Hours: Yamanashi vs. Okinawa
Source: Japan Meteorological Agency (Reference period: 1991–2020)
| Annual Sunshine Duration | |
|---|---|
| Okinawa | 1,727hours |
| Yamanashi | 2,226hours |
Compared to Yamanashi Prefecture, which ranks first in Japan, Okinawa has about 500 fewer sunshine hours per year—roughly equivalent to 8.3 days.
However, looking at the graph, Okinawa actually exceeds Yamanashi in sunshine hours from around July to September, showing that summer in Okinawa has many clear, sunny days.
In contrast, winter sunshine hours drop to less than half of summer levels, with January and February being the shortest and cloudiest months.
Overall, while Okinawa has fewer annual sunshine hours than many regions in Japan, this is largely due to the significantly low sunshine in winter.
In summer, Okinawa often features beautiful blue skies and sea views, but sudden squalls can still occur, so it’s important to stay prepared for quick weather changes.
Annual Number of Sunny Days in Okinawa
Okinawa records 211 sunny or clear days out of 365, ranking 35th in Japan.
For comparison, Kagawa Prefecture ranks 1st with 249 sunny days, while the national average is 217 days.
Even though Okinawa often has sunny periods in summer, frequent typhoons and sudden thunderstorms lower the overall ranking. This reflects Okinawa’s unique climate, surrounded by warm ocean waters and without high mountains to block weather systems.
After the rainy season ends in June, Okinawa is often covered by the Pacific High-pressure system, bringing many sunny days.
From September into autumn, sunny weather continues to be common, and warm conditions last until around late October.
From late November through winter, however, cloudy and rainy days become more frequent, making it harder to feel the typical “tropical island” atmosphere during this season.
Okinawa’s UV Levels
▼UV Index Comparison: Naha, Sapporo, and Tsukuba
| Annual Average (kJ/㎡) | |
|---|---|
| Naha | 21.01 |
| Sapporo | 11.02 |
| Tsukuba | 13.89 |
Okinawa’s UV levels remain high throughout the year, and in summer they can be about twice as high as those in Sapporo or Tsukuba.
The summer sunlight in Okinawa can feel intense enough to be painful on the skin.
Interestingly, the UV levels in Sapporo and Tsukuba during summer are similar to those in Okinawa during spring and autumn.
While many people are careful about sun protection in summer due to the strong sunlight, it’s important to note that other seasons also require caution.
When visiting Okinawa, it’s best to remember that UV protection is necessary not only in summer but throughout the entire year.
Recommended Items for UV and Sun Protection
Here are some recommended items for dealing with Okinawa’s strong UV rays and sunlight:
▼Recommended items
- Light long-sleeve T-shirts
- Light long pants
- Sunglasses
- Sun umbrella
- Sunscreen
- Hat
- Rash guard (to wear over swimwear)
- Arm sleeves (useful while driving)
Swimming in Okinawa during summer in just a swimsuit can be a bit risky.
At the beach, you are exposed not only to direct sunlight but also to UV rays reflected from the white sand and blue ocean.
In severe cases, this can lead to sunburn-like skin damage, so wearing a rash guard or a quick-dry T-shirt over your swimwear is recommended.
Some people may not like wearing long sleeves and pants in Okinawa’s summer heat.
In that case, make sure to reapply sunscreen frequently and use sunglasses and a hat to properly protect yourself from UV rays and strong sunlight.
Even in winter, when sunlight feels weaker, UV levels can still be comparable to summer in places like Sapporo or Tsukuba—so don’t forget sun protection year-round.
Travel Okinawa with GO!GO!TOUR Rent a Car
In this article, we introduced Okinawa’s sunshine hours and UV exposure.
Since many travelers get around Okinawa by rental car, don’t forget to take sun protection measures even while driving.
Have you already booked your rental car to fully enjoy the island?
For finding a rental car in Okinawa, “GO!GO!TOUR Rent a Car” is highly recommended.
Use the “GO!GO!TOUR Rent a Car” comparison site to book your vehicle at the best possible price!
