Weather in Onitsha, month by month

Warmest month: March, 26.8
Coldest month: January, 24.5
Wettest month: September, 315 mm
Year: 2001-2020

Weather in Port Harcourt, month by month

Same data, same method, different place.

Your own numbers, worked out on the page.

Across the 2001-2020 normals, the warmest month in Onitsha is March at 26.8 degrees and the coldest is January at 24.5, a swing of 2.4 degrees over the year. Those are monthly averages for the model cell the city sits in, not readings from a weather station in it.

Rain is heaviest in September, about 315 mm, and lightest in January at roughly 12 mm. Over a full year the cell above Onitsha collects around 1,705 mm.

No month in Onitsha averages between 15 and 24 degrees, so the year does not pass through what this page calls mild at all.

Humidity peaks in September at 90 percent, and the windiest month is August at 2.2 metres per second. Both are monthly means from the same twenty year series as the temperatures.

Rainfall is not spread evenly: 82 per cent of the year total falls in May, June, July, August, September and October.

Every figure here comes from one NASA POWER grid cell, at 6.15, 6.79, covering Onitsha on the 2001-2020 climatology. One cell, one period and one provider for every month, which is what makes the twelve rows comparable with each other.

The source publishes a monthly mean and, separately, the highest and lowest values it recorded in twenty years. Those extremes are not a typical afternoon or a typical night, so nothing here is quoted as one. This page does not say what the daytime high usually is, because this source cannot say it.

Normals are not a forecast. They describe what twenty years averaged to, and any single year can sit well outside them. They also describe a model grid cell of roughly fifty kilometres rather than a weather station, so a coastal city and the sea beside it share one figure.