Weather in Bangkok in May

A hard month. May is a hard month in Bangkok, and worth planning around. You should expect rain on 22 days of the month, which is more days wet than dry.

May ranks 12 of 12 — near the bottom of Bangkok's year. December is the month that works, and the swing between the two is 45 points, which is a different holiday rather than a slightly better one.

Rain on 22 of the month's 31 days, 6 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Pack for 33.9 °C days and 26 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 10 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest May day reached 42 °C and the coldest night fell to 23.3 °C, and the wettest single day dropped 43 mm — roughly 26% of the month's rain in one day.

May is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest May on record still delivered 351 mm against 43 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 164 mm average is a reasonable planning figure, not a promise.

Wind is light at 6.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 76%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way down: 2.7 °C cooler than April, with June dropping another 1.6 °C. The first week and the last are not the same trip. Rain has already shifted: 10 days more than April had.

Daylight in May

Bangkok sits close enough to the equator that daylight barely moves all year — 12.8 hours in May, against a range of just 1.6 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

An inland climate

Despite being inland, the year stays fairly even: 17.1 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Bangkok versus nearby

If Bangkok is one option among several, the nearby comparison is worth making. Lat Krabang is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Hua Hin is close enough to be a coin toss — within a degree on temperature, 5 days more rain.

So: May is a compromise. December is 45 points better and is what Bangkok is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Bangkok

See all twelve months in Bangkok, or where else to go in May.