Weather in Bangkok in May

How May compares

May is the 3rd warmest month of the year in Bangkok and ranks 4th of 134 destinations we compare for May - see where else is hot in May. Within Thailand it is 1st of 6 (Thailand in May). Against London's average high of 16.6°C in May, Bangkok is 16.7°C warmer by day and 18.2°C warmer at night.

Daytime and night-time in May

The typical May day in Bangkok peaks at 33.3°C, but that is an average: the warmest 10% of days reach 36.5°C or more. About 100% of days top 25°C and almost every pass 30°C. Nights average 26.5°C; one night in ten drops to 25.1°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest May day here reached 39.3°C (2010-05-10) and the coldest night 23.4°C (2007-05-07).

Rain in May

Wet (more than 8 rainy days): about 20 days with 1 mm or more, 135 mm in total. Year to year it varies a lot - the wettest May was 2017 with 334 mm, the driest 1992 with 49 mm. Humidity averages 76%, which makes the heat feel heavier than the thermometer suggests.

Sea temperature in May

The sea averages 30.6°C - warm enough to swim (22°c+). Depending on the year it ranges from 29.8°C to 31.3°C. This is the warmest the sea gets here all year.

Sunshine and daylight

Around 2.6 hours of sunshine a day (estimated from cloud cover), 12.6 hours of daylight: the sun rises about 05:51 and sets about 18:37 local time in mid-May. Average cloud cover is 79%.

Is May a good time to visit Bangkok?

May is not the strongest month here: hot days and frequent rain. The best months for Bangkok on our scoring are December, January, November; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Plan around the heat, not just the rain

The heat is the main constraint on a May visit. Humidity averages 76%, so light clothing alone may not make long periods outside comfortable. The hottest days can be more demanding: the warmest 10% reach 36.5°C or more. Keep outdoor plans flexible, avoid making midday your busiest stretch, and allow time for air-conditioned breaks. Loose, breathable clothes and comfortable footwear make more sense than heavy layers, while drinking water regularly should be part of your routine. Nights remain warm rather than fresh, so do not expect an evening walk to bring much relief. A room with effective cooling is a sensible priority.

Expect wet days without writing off the trip

Rain is frequent enough that a tightly packed outdoor itinerary is a poor fit. Carry a compact umbrella or light waterproof, and keep an indoor alternative ready rather than relying on a dry forecast for every outing. Sunshine averages about 2.6 hours within 12.6 hours of daylight, so long days do not mean consistently sunny skies. The figures do not tell you when rain will fall or how long each spell will last; avoid assuming it will always wait until later. May suits a flexible city stay better than a trip built around clear weather. December, January and November are the better-rated months overall.