Chiang Mai records about 1100mm of rain across roughly 87 wet days a year, which is a 24% chance on an average day. August is the wettest month at 225mm (20% of the annual total) and February the driest at 5mm. Local rain type: monsoon. Chiang Mai has a clear dry season (November-April) and monsoon season. The burning season (February-April) creates smoke haze — check air quality.
Chance of rain on an average day: 24%
Rainfall climatology for Chiang Mai. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 1100mm |
| Rain days per year | 87 |
| Odds on an average day | 24% |
| Wettest month | August — 225mm over 17 days |
| Driest month | February — 5mm over 1 days |
| Rain type | monsoon |
| Best dry window | November through February offers cool, dry weather — the most pleasant time to explore temples and night markets. |
| Worst rain window | August and September bring the heaviest monsoon rain — waterfalls are spectacular but some temple roads become impassable. |
August delivers 4400% more rain than February (225mm vs 5mm). That gap is the difference between planning around showers and ignoring them.
20% of the year's rain falls in August alone, so Chiang Mai has a genuine wet season rather than evenly spread showers.
Chiang Mai rain arrives in short, heavy bursts — shelter and timing matter more than gear.
Rain falls on about 17 days in August against 1 in February — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 7mm | 1 | 3% | 29°C |
| February | 5mm | 1 | 3% | 29°C |
| March | 15mm | 1 | 3% | 30°C |
| April | 50mm | 4 | 13% | 32°C |
| May | 158mm | 12 | 40% | 33°C |
| June | 130mm | 10 | 33% | 35°C |
| July | 155mm | 12 | 40% | 36°C |
| August | 225mm | 17 | 57% | 36°C |
| September | 220mm | 17 | 57% | 35°C |
| October | 122mm | 9 | 30% | 33°C |
| November | 40mm | 3 | 10% | 32°C |
| December | 10mm | 1 | 3% | 30°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Chiang Mai we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Chiang Mai records rain on roughly 87 days a year — about a 24% chance on any given day — totalling around 1100mm.
August, with about 225mm over 17 rain days. That is 20% of the entire year's rainfall in a single month.
February is the driest month at 5mm across roughly 1 days. November through February offers cool, dry weather — the most pleasant time to explore temples and night markets.
Chiang Mai has a clear dry season (November-April) and monsoon season. The burning season (February-April) creates smoke haze — check air quality.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.