Thailand Weather in September
In Bangkok and Pattaya it is hot and rainy, with highs of 88°F (31°C) and the sea at 86°F (30°C). On the Andaman coast it is warm and rainy, with highs of 85°F (29°C) and the sea at 85°F (30°C). On the Gulf islands it is warm and showery, with highs of 85°F (30°C) and the sea at 87°F (30°C). Rating: Good — most comfortable on the Gulf islands.
Goodcomfortable overall, but rain is frequent, on the Gulf islands
Climate normals checked September 29, 2026 · Source: Open-Meteo (ERA5) · How we calculate
Thailand weather in September by region
| Region | Day high | Night low | Sea | Rainy days | Rainfall | Humidity |
|---|---|---|---|---|---|---|
| Bangkok & Pattayacentral, eastern Gulf | 88°F (31°C) | 77°F (25°C) | 86°F (30°C) | 26 | 11.5 in (293 mm) | 83% |
| Andaman coastKrabi, Khao Lak | 85°F (29°C) | 76°F (24°C) | 85°F (30°C) | 25 | 10.4 in (265 mm) | 88% |
| Gulf islandsKoh Samui, Koh Phangan | 85°F (30°C) | 78°F (26°C) | 87°F (30°C) | 20 | 5.7 in (145 mm) | 81% |
Flight time from the US
We're still checking flight times from JFK, LAX and SFO to Thailand. This block will show them once our flight data is ready.
Other months in Thailand
- Jan88°FJanuary: Excellent
- Feb90°FFebruary: Excellent
- Mar86°FMarch: Excellent
- Apr88°FApril: Good
- May88°FMay: Good
- Jun88°FJune: Excellent
- Jul87°FJuly: Good
- Aug87°FAugust: Good
- Sep85°FSeptember: Good
- Oct84°FOctober: Mixed
- Nov88°FNovember: Excellent
- Dec88°FDecember: Excellent
Excellent Good Mixed Off-season
Phuket weather in September
Mixedrain is frequent
Thailand in September: FAQ
What's the weather like in Thailand in September?
In Bangkok and Pattaya it is hot and rainy, with highs of 88°F (31°C) and the sea at 86°F (30°C). On the Andaman coast it is warm and rainy, with highs of 85°F (29°C) and the sea at 85°F (30°C). On the Gulf islands it is warm and showery, with highs of 85°F (30°C) and the sea at 87°F (30°C).
Is September a good time to visit Thailand?
We rate September as Good. Yes — most comfortable on the Gulf islands, with highs of 85°F (30°C) and about 5.7 in (145 mm) of rain.
Is September rainy season in Thailand?
Driest on the Gulf islands, with about 5.7 in (145 mm) of rain and 20 rainy days. In Bangkok and Pattaya: 11.5 in (293 mm); On the Andaman coast: 10.4 in (265 mm).
How does Thailand in September compare to October?
October rates Mixed, September rates Good. In the best region, September brings highs of 85°F (30°C) and 5.7 in (145 mm) of rain; October brings 84°F (29°C) and 8.7 in (220 mm).
Where the data comes from
- Air temperature, rainfall, humidity — ERA5 reanalysis (Copernicus / ECMWF) via Open-Meteo, averaged over 2015–2024. Each region uses one point: the resort or city in its caption.
- Sea temperature — Open-Meteo Marine, average sea surface temperature for 2023–2026 (the source has no longer record yet).
- Rainy days — days with at least 1 mm (0.04 in) of rain. Reanalysis picks up light rain more often than weather stations, so treat this as an upper bound.
- Month rating — one rule for every destination, based on three factors: day highs (ideal 75–91°F / 24–33°C), monthly rainfall (ideal under 80 mm / 3.1 in) and, for beach regions, sea temperature (ideal 77°F / 25°C or warmer). All ideal means Excellent; one slightly weaker factor means Good. Mixed means heavy rain (150 mm / 5.9 in or more), highs above 97°F (36°C) or a sea below 70°F (21°C). Off-season means highs of 100°F (38°C) or more, cold below 54°F (12°C), over 350 mm (13.8 in) of rain, or several problems at once. A country's rating follows its best region, so check the regional table.
Checked September 29, 2026. Climate normals are refreshed yearly and the notes every 90 days. These are long-term averages, not a forecast: any given year can differ.
