Haikou is warmest in July, averaging 32° by day and 27° at night. The wettest month is October with 477 mm, and the year brings about 2049 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 22° | 17° | 34 mm | 20° | 10.9 h | Sightseeing |
| February | 23° | 18° | 48 mm | 20° | 11.3 h | Sightseeing |
| March | 27° | 20° | 47 mm | 22° | 11.9 h | Beach weather |
| April | 29° | 23° | 75 mm | 24° | 12.5 h | Beach weather |
| May | 31° | 26° | 205 mm | 27° | 13.0 h | Rainy season |
| June | 31° | 27° | 177 mm | 29° | 13.2 h | Mild |
| July | 32° | 27° | 211 mm | 30° | 13.1 h | Rainy season |
| August | 31° | 27° | 276 mm | 30° | 12.7 h | Rainy season |
| September | 30° | 26° | 357 mm | 29° | 12.1 h | Rainy season |
| October | 28° | 25° | 477 mm | 28° | 11.5 h | Rainy season |
| November | 26° | 22° | 114 mm | 25° | 11.0 h | Mild |
| December | 22° | 18° | 28 mm | 22° | 10.8 h | Sightseeing |
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: March and April — highs around 28°, nights no colder than 20°, and at most 75 mm of rain in a month. The sea sits at 22–24° then.
Walking the city: January, February and December — highs of 22–23° and no more than 48 mm of rain a month.
Wet season: May, July, August, September and October — up to 477 mm in a single month.