Bangkok in May

May is the official start of Bangkok's rainy season, but the first half of the month often still feels like hot season — short, dramatic afternoon thunderstorms (the famous 'mango showers') give brief relief but soon evaporate into steamy humidity. Average highs ease back to 34 °C from April's 36 °C, and finally the PM2.5 stops being a daily concern as the southwest monsoon flushes the air clear. Crowds thin dramatically after Songkran ends, and hotel rates drop into the year's true shoulder zone. For the first time since November, restaurant and rooftop reservations become trivial to land.

Rain in May follows a predictable rhythm: blue skies all morning, an aggressive 30–90-minute downpour between 14:00 and 18:00, then clear evenings. Plan outdoor sightseeing — Grand Palace, Chatuchak Market, Bang Krachao cycling — for mornings before the rain. May also brings the Royal Ploughing Ceremony at Sanam Luang (varies, late April or May), a fascinating Brahmin ritual marking the start of rice-planting season — Thailand's only royal ceremony where you can still witness royal oxen pulling a ceremonial plough.