Chiang Mai in Fall
In fall (September, October and November), Chiang Mai sees average daytime highs around 31°C and overnight lows near 22°C, with 362 mm of rain over about 43 wet days across the season. It is the 3rd-warmest season and the 2nd-wettest season.
Across fall, daytime highs hold fairly steady around 31°C. The sky is clear or mostly clear about 31% of the time across fall, and the air most often feels oppressive.
Fall is Chiang Mai's 2nd-best season to visit on our travel score. For the whole year in context, see Chiang Mai's year-round climate.
- Avg daytime high
- 31°C
- 3rd-warmest season
- Avg overnight low
- 22°C
- Rainfall
- 362 mm
- 43 wet days
- Avg wind
- 4 km/h
- Travel score
- 4.2
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Chiang Mai in Fall
Across fall, daytime highs hold fairly steady around 31°C.
A typical fall day in Chiang Mai reaches about 31°C and drops to 22°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Chiang Mai
Once humidity and wind are folded in, fall brings about 78 days that feel above 32°C and 0 that feel at or below 0°C.
The story in fall is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Chiang Mai weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 30° / 15° | 7 | 1.3 | 11 | 6.7 |
| Feb | 33° / 17° | 3 | 0.7 | 11.4 | 5.0 |
| Mar | 35° / 20° | 12 | 2.1 | 11.9 | 3.1 |
| Apr | 37° / 24° | 26 | 4.4 | 12.4 | 1.9 |
| May | 35° / 25° | 99 | 13.2 | 12.9 | 2.3 |
| Jun | 33° / 25° | 120 | 18.3 | 13.1 | 2.5 |
| Jul | 32° / 25° | 175 | 21.9 | 13 | 2.6 |
| Aug | 31° / 25° | 236 | 25.1 | 12.6 | 2.7 |
| Sep | 31° / 24° | 227 | 23.4 | 12.1 | 2.8 |
| Oct | 31° / 22° | 114 | 15.7 | 11.6 | 4.0 |
| Nov | 30° / 19° | 21 | 4 | 11.1 | 5.8 |
| Dec | 29° / 16° | 9 | 1.2 | 10.9 | 7.2 |
Cloud cover in Fall
The sky is clear or mostly clear about 31% of the time across fall.
Chance of precipitation in Fall
Chiang Mai gets around 362 mm of rain over 43 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 4 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 24 min in early September to 11 hours by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 4.3 kWh/m².
Hazard calendar for Chiang Mai
In fall, Chiang Mai overlaps its monsoon season. The full year is below, with each hazard's peak months called out.
Chiang Mai's monsoon runs June–October, when most of the year's rain falls.
Is fall a good time to visit Chiang Mai?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit Chiang Mai for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Chiang Mai in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Chiang Mai sees daytime highs around 31°C and nights near 22°C. Pack light clothes and rain gear. About 43 days see rain.
UV index in Chiang Mai in Fall
Clear-sky midday UV across fall averages around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Chiang Mai peaks around August 13 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 7 (very high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 7 | 9 | 9 | 10 | 12 | 13 | 13 | 14 | 12 | 10 | 8 | 7 |
| Level | Very high | Very high | Very high | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Very high |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 7 | Very high |
| Feb | 9 | Very high |
| Mar | 9 | Very high |
| Apr | 10 | Very high |
| May | 12 | Extreme |
| Jun | 13 | Extreme |
| Jul | 13 | Extreme |
| Aug | 14 | Extreme |
| Sep | 12 | Extreme |
| Oct | 10 | Extreme |
| Nov | 8 | Very high |
| Dec | 7 | Very high |
Air quality in Chiang Mai in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in Chiang Mai is worst in March — around 69 µg/m³ PM2.5 (unhealthy), about 4.3× the cleanest month (July, 16 µg/m³).
Seasonal pattern from CAMS reanalysis, scaled to Chiang Mai's WHO annual average of 33 µg/m³.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 37 | 46 | 69 | 60 | 28 | 16 | 16 | 17 | 21 | 25 | 28 | 32 |
| Level | Poor | Poor | Unhealthy | Unhealthy | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 37 | Poor |
| Feb | 46 | Poor |
| Mar | 69 | Unhealthy |
| Apr | 60 | Unhealthy |
| May | 28 | Moderate |
| Jun | 16 | Moderate |
| Jul | 16 | Moderate |
| Aug | 17 | Moderate |
| Sep | 21 | Moderate |
| Oct | 25 | Moderate |
| Nov | 28 | Moderate |
| Dec | 32 | Moderate |
Where is Chiang Mai?
Chiang Mai sits at 18.8°N, 99.0°E, 313 m above sea level, in Thailand. The nearest listed city is Hang Dong, 13 km away.
Topography around Chiang Mai
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Chiang Mai.
Within 3 km, the terrain around Chiang Mai has only modest variations in elevation — a maximum elevation change of 45 m around an average of 313 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,399 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,341 m.
The land around Chiang Mai is covered by artificial surfaces (72%) and trees (22%) within 3 km, trees (57%) and artificial surfaces (21%) within 16 km, and trees (84%) within 80 km.
Thailand travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B / C
- 230 V · 50 Hz
- Prices
- ≈ 31% of US
- price level, 2025
- GDP per capita
- $8,057
- 2025
- Happiness
- 6.3 / 10
- World Happiness, 2025
- Homicide rate
- 4.8
- per 100k, 2011
- Road deaths
- 32.2
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Very low
- EF EPI 402
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Chiang Mai (18.7904°, 98.9847°, elevation 313 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.