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Chiang Rai Weather in September
In Chiang Rai, September brings very high daytime temperatures around 32°C (90°F), with nights cooling to 24°C (75°F). This month falls within the rainy season, so expect frequent rainfall.
Rainfall in Chiang Rai in September
Chiang Rai is in the rainy season in September, with rain on around 18 days and an average of 290 mm (11 in). The rain this month falls heavily when it arrives. Late afternoons in particular can see strong showers, so waterproofs are worth keeping handy.
Temperature in Chiang Rai in September
September in Chiang Rai brings very high temperatures, with highs of 32°C (90°F) and nights around 24°C (75°F). Sunshine and humidity can make it feel even warmer than the raw temperature suggests. At 24°C (75°F) overnight, it stays warm after dark. Light, breathable clothing and good airflow in your room make a noticeable difference.
Sunshine in Chiang Rai in September
You can expect a moderate amount of sunlight, with approximately 145 hours. Even though this month is part of the wet season, you can still see the sun occasionally.Our weather planner can help you find worldwide destinations with pleasant weather during this period. December typically offers the best weather for Chiang Rai.
Chiang Rai Temperature in September
Min Temperature
24°C (75°F)
Max Temperature
32°C (90°F)
Chance of Rain
59%
Precipitation
290 mm (11 in)
Rainy days
18 days
Humidity
83%
Sunshine
145 hours
Percentage Sunshine
Chiang Rai Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Chiang Rai - and find the best time to visit.
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Chiang Rai typically stay consistent throughout September, with daily highs averaging around 32°C (90°F). Nights are warm, with lows around 23°C (73°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather records for Chiang Rai in September
Browse day-by-day weather records for Chiang Rai spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Chiang Rai historical weather extremes in September
Based on 49 years of weather observations in Chiang Rai between 1976 and 2025, these are the recorded extremes.
- Chiang Rai recorded its highest September temperature of 36°C (97°F) on September 1, 1983.
- The lowest daytime temperature in September was 23°C (73°F), recorded on September 10, 2004.
- The coldest night in September in Chiang Rai was on September 25, 1986, with a minimum of 18°C (64°F).
- The heaviest September precipitation occurred on September 4, 2001, when 160 mm (6.3 in) of precipitation fell.
Best Places in Thailand in September
Find out more about the weather in Thailand and which places have the best travel conditions in this month. See all of Thailand in September →
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
What to Wear in Chiang Rai in September
Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). Also bring a poncho, it will rain a lot! Waterproof everything you can. Sunglasses could come in handy during the sunnier parts of your trip.
What To Do in Chiang Rai in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
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Swimming7/10 -
Cycling7/10 -
Walking7/10 -
Camping6/10 -
Outdoor sports7/10
Chiang Rai 3-Day Forecast
More climate data for Chiang Rai
Temperature Rainfall Sunshine Humidity
See the full Chiang Rai climate overview or explore weather in Thailand.
Popular in September
Where to go in September - average daytime high across popular destinations.
Bangkok
34°C (93°F) Chiang Mai33°C (91°F) Jomtien Beach32°C (90°F) Hua Hin32°C (90°F) Ao Nang Beach30°C (86°F) Koh Samui30°C (86°F) Ko Lanta30°C (86°F) Patong Beach29°C (84°F) Bucket list
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