Bangkok's most walkable months: December's 19 mm of rain vs September's 297 mm
Bangkok works year-round, true — but the "walk the city all day" experience differs enormously between a 19 mm month and a 297 mm month. Here are the 10-year monthly means at Bangkok's coordinate — the same dataset rooozt's weather calendar uses.
The real monthly numbers (mm/month, 2016–2025 means)
The full year looks like this:
- Dec 19 · Jan 23 · Feb 35 — three genuinely dry months, all under the 50 mm "dry month" threshold
- Mar 45 · Apr 84 — clearly hotter, rain still light
- May–Aug 179 / 152 / 207 / 193 — full rainy season, afternoon rain as routine
- Sep 297 — the wettest month of the year by a distance · Oct 245 close behind
- Nov 82 — the season's exit door: rainfall drops fast from the month before
Translating that into a trip plan
The golden window for long outdoor days — Grand Palace, Charoenkrung, weekend markets — is Dec–Feb: the least rain, and the "cool season" when the air noticeably softens. December at 19 mm is the month with the lowest rain odds of the year.
Sep–Oct isn't automatically avoid-territory — most Bangkok rain arrives in late-afternoon-to-evening bursts and then stops, rather than falling all day. Plan outdoor mornings and mall/museum/café afternoons and you'll still see everything, at the softest room rates of the year — great for eating-and-shopping trips on a controlled budget.
Frequently asked questions
- Does November already count as high season?
- By the numbers it's already in the safe zone — 82 mm versus the 245–297 mm of the two months before. It's also Loy Krathong month, one of the Chao Phraya's most beautiful nights, so riverside stays get booked out unusually fast.
Where the numbers come from: Every rainfall figure in this article is a 2016–2025 monthly mean from the ERA5 dataset (via the Open-Meteo Historical Weather API) at each province's coordinate — a 10-year statistic, not a forecast for your trip. Any single year can differ a lot from the mean. This is the same dataset the weather calendar in rooozt's search bar displays.