Weather in Phnom Penh, month by month

Warmest month: April, 31.3
Coldest month: December, 26.7
Wettest month: September, 190 mm
Year: 2001-2020

Same data, same method, different place.

Your own numbers, worked out on the page.

Across the 2001-2020 normals, the warmest month in Phnom Penh is April at 31.3 degrees and the coldest is December at 26.7, a swing of 4.5 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 190 mm, and lightest in February at roughly 11 mm. Over a full year the cell above Phnom Penh collects around 1,242 mm.

No month in Phnom Penh 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 86 percent, and the windiest month is August at 2.5 metres per second. Both are monthly means from the same twenty year series as the temperatures.

Rainfall is not spread evenly: 81 per cent of the year total falls in May, June, July, August, September and October.

5 months average 28 degrees or more: February, March, April, May and June.

Every figure here comes from one NASA POWER grid cell, at 11.56, 104.92, covering Phnom Penh 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.