Chiang Mai in September
In September, Chiang Mai averages 31°C (88°F) during the day and 23°C (73°F) at night, with frequent rain — about 18 days of the month see precipitation (250 mm total).
ShoulderConditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.
September is one of the wetter and less comfortable months in Chiang Mai. If your dates are flexible, consider a different time of year.
How September compares to the rest of the year in Chiang Mai
September is in the middle of the year for warmth in Chiang Mai (8th of 12) and one of the wettest months (1st of 12). Daytime temperature runs 1°C below the annual average (32°C). September runs roughly the same as August (31°C) and stays flat into October.
September sunrise & sunset in Chiang Mai
Times shown for Chiang Mai local time (Asia/Bangkok), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Chiang Mai — September
Golden-hour and blue-hour windows for the 15th of September, in Chiang Mai's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Chiang Mai in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Shoulder) and Chiang Mai's popularity.
Crowds & pricing — September in Chiang Mai
Chiang Mai is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Sun & mosquito risk — September in Chiang Mai
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Chiang Mai in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 29°C / 84°F | 14°C / 57°F | 5 mm | 1 | 0 |
| February | 32°C / 90°F | 15°C / 59°F | 10 mm | 1 | 0 |
| March | 34°C / 93°F | 18°C / 64°F | 30 mm | 3 | 0 |
| April | 36°C / 97°F | 22°C / 72°F | 55 mm | 5 | 0 |
| May | 34°C / 93°F | 23°C / 73°F | 165 mm | 12 | 0 |
| June | 33°C / 91°F | 23°C / 73°F | 150 mm | 12 | 0 |
| July | 32°C / 90°F | 23°C / 73°F | 165 mm | 15 | 0 |
| August | 31°C / 88°F | 23°C / 73°F | 205 mm | 17 | 0 |
| September | 31°C / 88°F | 23°C / 73°F | 250 mm | 18 | 0 |
| October | 31°C / 88°F | 22°C / 72°F | 140 mm | 10 | 0 |
| November | 30°C / 86°F | 19°C / 66°F | 50 mm | 5 | 0 |
| December | 28°C / 82°F | 16°C / 61°F | 15 mm | 2 | 0 |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Chiang Mai in September →
Frequently asked questions
How hot is Chiang Mai in September?
In September, Chiang Mai averages a high of 31°C (88°F) and a low of 23°C (73°F) — generally hot.
Does it rain a lot in Chiang Mai in September?
September is quite rainy in Chiang Mai, with about 18 rainy days on average.
Is September a good time to visit Chiang Mai?
September is hot but on the rainy side. It suits travelers who are comfortable with hot weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Chiang Mai in September?
Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full September packing list for Chiang Mai for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.