Weather in Siem Reap in April

A hard month. April asks something of you. Go in knowing what. Daytime highs average 36 °C and the afternoon is not negotiable — outdoor plans move to early morning or evening.

April ranks 11 of 12 — near the bottom of Siem Reap's year. December is the month that works, and the swing between the two is 39 points, which is a different holiday rather than a slightly better one.

Rain on 13 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for heat management rather than style: shade, water, and a schedule that gives up on the middle of the day.

What the averages hide

Averages flatten a month, and this one hides a few things: 19 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest April day reached 43.3 °C and the coldest night fell to 19.5 °C, and the wettest single day dropped 30 mm — roughly 40% of the month's rain in one day.

April is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest April on record still delivered 130 mm against 26 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 75 mm average is a reasonable planning figure, not a promise.

Wind is light at 4.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 64%.

How April sits in the year

Temperatures hold steady either side: 36.7 °C in March, 36 here, 34.1 in May. Nothing about the timing within the month matters much. Rain is the thing that moves: May brings 9 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in April

Siem Reap sits close enough to the equator that daylight barely moves all year — 12.4 hours in April, against a range of just 1.6 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

An inland climate

Despite being inland, the year stays fairly even: 16.1 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

April in Siem Reap versus nearby

If Siem Reap is one option among several, the nearby comparison is worth making. Ubon Ratchathani is close enough to be a coin toss — within a degree on temperature, 2 days less rain. Nakhon Ratchasima is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: April is a compromise. December is 36 points better and is what Siem Reap is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Siem Reap

See all twelve months in Siem Reap, or where else to go in April.