Weather in Thailand in July

July climate overview

Daytime highs across Thailand in July run from 28.5°C (Phuket) to 31.7°C (Bangkok). In Bangkok about 100% of July days reach 25°C. Nights average 25.4°C; the coldest 10% of nights in Phuket fall to 25°C or below.

Rainfall in July

Expect around 23 rainy days (1 mm or more) in July, with Koh Samui the driest (19 days) and Khao Lak the wettest (26 days). The wettest July at Bangkok between 1991 and 2020 was 2017 with 253 mm; the driest was 2002 with 87 mm.

Sea temperature

The sea averages 29.4°C around Thailand in July - warmest at Krabi (29.6°C). That is comfortable for swimming.

Sunshine and daylight

Around 1.5 hours of sunshine a day on average, out of 12.7 hours of daylight (sunshine estimated from cloud cover).

July against the rest of the year in Thailand

July is the 6th warmest month of the twelve in Thailand. It is 0.5°C cooler than June and 0.3°C cooler in August. The hottest month here is April (32°C) and the coolest December (29°C).

Which part of Thailand in July?

• Most sunshine: Phuket, 1.8 h a day.
• Driest: Koh Samui, about 19 rainy days.
• Warmest sea: Krabi, 30°C.
• Hottest: Bangkok, 32°C by day.
• Coolest (better for walking and cities): Phuket, 29°C.

What to pack for Thailand in July

Based on the averages: summer clothes for the day; a rain jacket - roughly 23 wet days; swimwear - the sea is 29°C.

Similar weather elsewhere in July

Within 1.5°C of Thailand's July daytime average: Crete (31°C, sea 25°C), Hammamet (31°C, sea 25°C), Costa de la Luz (31°C, sea 23°C), Alanya (31°C, sea 28°C), Puerto Vallarta (31°C, sea 30°C). See the full ranking for July.

Koh Samui has the better beach-weather balance

Koh Samui offers the most favourable balance here, with 30°C days and 19 rainy days. That still means accepting wet weather, but it has fewer rainy days than the other destinations listed. Krabi and Khao Lak each have 26 rainy days, making them less appealing if time outdoors is your priority. Phuket is cooler at 28°C, though its 24 rainy days mean it is not a reliably dry alternative. For travellers choosing mainly on July weather, Koh Samui gets the nod. The catch is that even this relative advantage does not make it a dependable month for lounging in sunshine.

Bangkok is hottest; Chiang Mai offers cooler nights

Bangkok is the hottest option, reaching 32°C by day and staying at 26°C at night. If heat affects your energy, leave room for indoor breaks rather than filling the hottest part of the day with outdoor plans. Chiang Mai reaches 30°C, with nights easing to 24°C, so it offers a little more relief after dark. Both have 23 rainy days, so choosing Chiang Mai does not buy you fewer wet days. The decision is more about temperature: Bangkok suits those comfortable with stronger heat, while Chiang Mai is the gentler option for travellers who prefer a cooler evening.

Pack for warmth and rain, not cool weather

Across Thailand, the average night stays at 25°C, so light clothing is more useful than a wardrobe built around cool evenings. Pack something for rain and a way to keep belongings dry, and allow plans to move around the weather. The limited sunshine makes July a poor fit if clear skies are central to your holiday, even though temperatures remain high. Nor should a rainy-day figure be read as a promise about when rain will arrive or how long it will last. Treat outdoor time as flexible, with indoor alternatives ready, rather than assuming a fixed daily window of dry weather.