Weather in Chiang Mai in December

Prime time. December is about as good as Chiang Mai gets. Highs average 27.6 °C, lows 16.9 °C, and rain falls on 2 days — nothing in the month is working against you.

December is the highest-scoring month of the twelve. The nearest rival is January, and the month at the other end of the year is April.

Rain falls on only 2 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: 6 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest December day reached 33.1 °C and the coldest night fell to 7.9 °C.

This is the volatile part. December rainfall has ranged from 0 mm to 49 mm across the twenty years measured — a 49 mm spread around an average of 13 mm. The average is real but almost no individual December looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 76%, high enough to notice on the warm days without dominating them.

How December sits in the year

This is a turning point in the year — November and January sit on opposite sides of it, so the month contains the change rather than following it.

Daylight in December

December sits at the dark end of Chiang Mai's year — 11 hours of daylight against 13.3 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

Despite being inland, the year stays fairly even: 20.8 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

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

December in Chiang Mai versus nearby

If Chiang Mai is one option among several, the nearby comparison is worth making. Luang Prabang is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Udon Thani is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: December is the answer for Chiang Mai. If it is booked out or priced out, January is the next best thing at 6 points behind, and April is the month to keep off the shortlist.

Every month in Chiang Mai

See all twelve months in Chiang Mai, or where else to go in December.