Onitsha is warmest in February, averaging 31° by day and 23° at night. The wettest month is September with 330 mm, and the year brings about 1782 mm in total.
Month by month
| Month | High | Low | Rain | Daylight | Good for |
|---|---|---|---|---|---|
| January | 30° | 20° | 22 mm | 11.7 h | Beach weather |
| February | 31° | 23° | 8 mm | 11.8 h | Beach weather |
| March | 31° | 24° | 74 mm | 12.0 h | Beach weather |
| April | 31° | 24° | 129 mm | 12.1 h | Mild |
| May | 30° | 24° | 177 mm | 12.3 h | Mild |
| June | 29° | 23° | 273 mm | 12.4 h | Rainy season |
| July | 29° | 23° | 257 mm | 12.3 h | Rainy season |
| August | 29° | 22° | 208 mm | 12.2 h | Rainy season |
| September | 29° | 23° | 330 mm | 12.0 h | Rainy season |
| October | 29° | 23° | 205 mm | 11.9 h | Rainy season |
| November | 30° | 23° | 90 mm | 11.7 h | Beach weather |
| December | 30° | 20° | 9 mm | 11.6 h | Beach weather |
High and low are average daily maximum and minimum, rain is typical monthly total, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER — averages, not promises.
When to go
Beach weather: January, February, March, November and December — highs around 31°, nights no colder than 20°, and at most 90 mm of rain in a month.
Wet season: June, July, August, September and October — up to 330 mm in a single month.