Osaka is warmest in August, averaging 31° by day and 23° at night. The wettest month is August with 288 mm, and the year brings about 2082 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 8° | -1° | 68 mm | 13° | 9.9 h | Cool |
| February | 9° | -1° | 64 mm | 11° | 10.7 h | Cool |
| March | 14° | 2° | 155 mm | 12° | 11.7 h | Mild |
| April | 18° | 7° | 183 mm | 15° | 12.9 h | Rainy season |
| May | 22° | 12° | 223 mm | 18° | 13.8 h | Rainy season |
| June | 26° | 17° | 276 mm | 22° | 14.3 h | Rainy season |
| July | 29° | 22° | 260 mm | 26° | 14.1 h | Rainy season |
| August | 31° | 23° | 288 mm | 28° | 13.3 h | Rainy season |
| September | 28° | 19° | 237 mm | 27° | 12.2 h | Rainy season |
| October | 21° | 12° | 174 mm | 23° | 11.1 h | Mild |
| November | 16° | 7° | 111 mm | 19° | 10.1 h | Mild |
| December | 10° | 1° | 43 mm | 16° | 9.7 h | Cool |
High and low are average daily maximum and minimum, rain is typical monthly total, sea is the average surface temperature, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER and NOAA MUR — averages, not promises.
When to go
Beach weather: No month in Osaka combines swimming warmth with dry skies.
Wet season: April, May, June, July, August and September — up to 288 mm in a single month.