Chiang Rai in Fall
In fall (September, October and November), Chiang Rai sees average daytime highs around 29°C and overnight lows near 21°C, with 483 mm of rain over about 50 wet days across the season. It is the 3rd-warmest season and the 2nd-wettest season.
Over the season highs ease from about 30°C in early September to 27°C by late November. The sky is clear or mostly clear about 33% of the time across fall, and the air most often feels oppressive.
Fall is Chiang Rai's 2nd-best season to visit on our travel score. For the whole year in context, see Chiang Rai's year-round climate.
- Avg daytime high
- 29°C
- 3rd-warmest season
- Avg overnight low
- 21°C
- Rainfall
- 483 mm
- 50 wet days
- Avg wind
- 4 km/h
- Travel score
- 4.7
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Chiang Rai in Fall
Over the season highs ease from about 30°C in early September to 27°C by late November.
A typical fall day in Chiang Rai reaches about 29°C and drops to 21°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Chiang Rai
Once humidity and wind are folded in, fall brings about 50 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 Rai 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 | 28° / 14° | 22 | 3 | 10.9 | 7.7 |
| Feb | 31° / 15° | 13 | 2.4 | 11.3 | 5.9 |
| Mar | 33° / 18° | 42 | 5.1 | 11.9 | 4.1 |
| Apr | 34° / 21° | 132 | 11.8 | 12.4 | 3.1 |
| May | 32° / 23° | 292 | 22.8 | 12.9 | 2.8 |
| Jun | 31° / 24° | 297 | 26.2 | 13.2 | 2.5 |
| Jul | 31° / 24° | 398 | 28.4 | 13.1 | 2.6 |
| Aug | 30° / 24° | 383 | 28.8 | 12.7 | 2.6 |
| Sep | 30° / 23° | 295 | 25.1 | 12.1 | 3.0 |
| Oct | 30° / 22° | 139 | 17.8 | 11.5 | 4.4 |
| Nov | 28° / 18° | 49 | 6.7 | 11.1 | 6.7 |
| Dec | 26° / 15° | 27 | 3.7 | 10.8 | 8.0 |
Cloud cover in Fall
The sky is clear or mostly clear about 33% of the time across fall.
Chance of precipitation in Fall
Chiang Rai gets around 483 mm of rain over 50 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 10 h 54 min 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 Rai
In fall, Chiang Rai overlaps its monsoon season. The full year is below, with each hazard's peak months called out.
Chiang Rai's monsoon runs May–September, when most of the year's rain falls.
Is fall a good time to visit Chiang Rai?
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 Rai for sightseeing.
What to pack for Chiang Rai in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Chiang Rai sees daytime highs around 29°C and nights near 21°C. Pack light clothes and rain gear. About 50 days see rain.
UV index in Chiang Rai 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 Rai peaks around July 17 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 7 (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 | 11 | 13 | 13 | 13 | 11 | 10 | 8 | 7 |
| Level | Very high | Very high | Very high | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Very high | High |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 7 | Very high |
| Feb | 9 | Very high |
| Mar | 9 | Very high |
| Apr | 10 | Very high |
| May | 11 | Extreme |
| Jun | 13 | Extreme |
| Jul | 13 | Extreme |
| Aug | 13 | Extreme |
| Sep | 11 | Extreme |
| Oct | 10 | Very high |
| Nov | 8 | Very high |
| Dec | 7 | High |
Air quality in Chiang Rai 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 Rai is worst in April — around 142 µg/m³ PM2.5 (unhealthy), about 12.0× the cleanest month (July, 12 µg/m³).
Seasonal pattern from CAMS reanalysis, scaled to Chiang Rai's WHO annual average of 37 µg/m³.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 21 | 36 | 117 | 142 | 34 | 14 | 12 | 12 | 12 | 13 | 14 | 17 |
| Level | Moderate | Poor | Unhealthy | Unhealthy | Moderate | Moderate | Good | Good | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 21 | Moderate |
| Feb | 36 | Poor |
| Mar | 117 | Unhealthy |
| Apr | 142 | Unhealthy |
| May | 34 | Moderate |
| Jun | 14 | Moderate |
| Jul | 12 | Good |
| Aug | 12 | Good |
| Sep | 12 | Moderate |
| Oct | 13 | Moderate |
| Nov | 14 | Moderate |
| Dec | 17 | Moderate |
Where is Chiang Rai?
Chiang Rai sits at 19.9°N, 99.8°E, 401 m above sea level, in Thailand. The nearest listed city is Mae Chan, 27 km away.
Topography around Chiang Rai
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Chiang Rai.
Within 3 km, the terrain around Chiang Rai has only modest variations in elevation — a maximum elevation change of 66 m around an average of 398 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 815 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,937 m.
The land around Chiang Rai is covered by artificial surfaces (43%) and trees (36%) within 3 km, trees (52%) and cropland (33%) within 16 km, and trees (70%) and cropland (21%) 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 Rai (19.9086°, 99.8325°, elevation 401 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.