Thailand weather by month

In Bangkok, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around October 25 and lasts for 6.2 months, ending around May 2. The clearest month is February, when the sky is clear, mostly clear, or partly cloudy 82% of the time on average.

The cloudier part of the year begins around May 3 and lasts for 5.7 months, ending around October 24. The cloudiest month is August, when it is overcast or mostly cloudy 94% of the time.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Bangkok is typically calm, near 9 km/h, and varies little with the seasons.

The windier part of the year lasts 6.6 months, from around Feb 9 to Aug 28. The windiest month is March, averaging about 11 km/h (calm).

The calmer part of the year runs from around Aug 29 to Feb 8, with October the calmest month at about 7 km/h.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Bangkok receives about 5.2 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.5 and 6.3 kWh/m².

The brighter stretch of the year lasts 4.6 months, from around Jan 26 to Jun 14. The brightest month is April, averaging about 6.2 kWh/m² (intense).

The dimmest month is October, down near 4.6 kWh/m² — roughly 25% less than the April peak.