Doi Inthanon Weather

Doi Inthanon is cold at the top and often in cloud. The Department of National Parks says the summit can fall to 0 to 4 degrees on frosty days in December and January, and that above 1,800 m the forest is in cloud and fog for most of the year. December is the month that balances it best: in Chiang Mai it brings little rain (14.1 mm on the long-term average) and fewer hazy days than January to April. For a December day, book TripGuru Thailand’s Chiang Mai: Doi Inthanon, Twin Pagodas & Waterfalls Day Tour, from US$38 a person (checked November 2026; on 15 December 2026 the meeting-point option without fees cost US$38.66), and bring a jacket.

Free cancellation until 24 hours before, so you can move the day if the forecast turns.

The park’s seasons

The park splits the year three ways: summer from March to May, a rainy season from June to November, and winter from December to February. The upper slopes are wet and cold all year. At the summit there can be gale-force winds and temperatures below freezing, and on frosty days in December and January it may fall to 0 to 4 degrees. In the park’s central area the average is about 20 degrees, and 15 to 17 degrees in December and January. Rainfall is 2,000 to 2,100 mm a year.

On 20 October 2026, before the cold season had properly begun, The Nation reported the park’s morning reading as 9 degrees at the summit and 12 at Kew Mae Pan.

Chiang Mai, month by month

There is no long-term weather station on the mountain in the national normals we read, so the nearest record is Chiang Mai, where the tours start and end.

Thai Meteorological Department, climate normals 1991 to 2020, Chiang Mai station (checked November 2026). “Not shown”: we did not take those values from the table.

The dry months are December to February. The haze climbs through the same months, to 22 days in February and 27 in March. November is still the tail of the park’s rainy season.

What reviewers found at the top

TripGuru Thailand’s day goes to the summit and the pagodas before lunch. In its 350 most recent reviews, dated 11 September to 10 November 2026, fog at the top comes up several times in October: a 15 October reviewer found it cold and misty with no view from the summit, and reviewers on 11, 14 and 27 October had fog on the mountain (at the pagodas, on 11 October). The 27 October reviewer wished the stops had been taken in a different order because of the morning fog. On 5 November a reviewer still enjoyed the pagodas “even with the cloudy weather”.

What to wear

TripGuru Thailand’s packing list has a jacket and an umbrella as well as sun cream and comfortable shoes, and the pagodas need shoulders and knees covered. A warm layer you can take off on the way down is the useful piece: Chiang Mai’s average high in January is 30 degrees, while the summit can be near freezing.

Pick a December date

Is the park open?

Yes. The national parks department’s closure list showed no closure for Doi Inthanon on 10 November 2026. The Kew Mae Pan trail opened for the season on 1 November 2026, and the Pha Dok Siao trail and Mae Ya waterfall, closed after flash floods on 19 September, reopened on 30 September 2026, the park’s Facebook page says. The Kew Mae Pan nature trail covers the trail season.