Weather in Phuket in September

How September compares

September is the 11th warmest month of the year in Phuket and ranks 48th of 134 destinations we compare for September - see where else is hot in September. Within Thailand it is 6th of 6 (Thailand in September). Against London's average high of 18.6°C in September, Phuket is 9.4°C warmer by day and 14.4°C warmer at night.

Daytime and night-time in September

The typical September day in Phuket peaks at 28.0°C, but that is an average: the warmest 10% of days reach 29.0°C or more. About 100% of days top 25°C and 1 in 32 pass 30°C. Nights average 25.6°C; one night in ten drops to 24.3°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 31.5°C (2018-09-21) and the coldest night 23.4°C (1999-09-28).

Rain in September

Wet (more than 8 rainy days): about 25 days with 1 mm or more, 297 mm in total. Year to year it varies a lot - the wettest September was 1991 with 488 mm, the driest 2018 with 111 mm. Humidity averages 83%, which makes the heat feel heavier than the thermometer suggests.

Sea temperature in September

The sea averages 28.9°C - warm enough to swim (22°c+). Depending on the year it ranges from 28.4°C to 29.6°C. For the warmest sea here, come in April (30.2°C).

Sunshine and daylight

Around 1.6 hours of sunshine a day (estimated from cloud cover), 12.0 hours of daylight: the sun rises about 06:17 and sets about 18:27 local time in mid-September. Average cloud cover is 87%.

Is September a good time to visit Phuket?

It is a reasonable choice: hot days but expect showers. The best months for Phuket on our scoring are February, January, March; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Hot and humid, with little cooling after dark

September is relatively cool for Phuket, but it will still feel hot coming from the UK. Average nights stay around 26°C, so do not expect evenings to bring much relief. Humidity of 83% adds to the discomfort, making loose, breathable clothing more useful than heavy layers. Air conditioning is worth prioritising if warm nights affect your sleep. Keep midday plans undemanding and leave room for breaks rather than packing your schedule. The sea averages 28.9°C, comfortably warm for swimming without a cold-water shock. That warmth is a reason to go, although it does not guarantee suitable swimming conditions; follow local safety advice before entering the water.

Plan around rain, not guaranteed sunshine

With about 25 rainy days and just 1.6 hours of sunshine a day, September is a poor fit if your holiday depends on long sunny spells. There is still daylight for outdoor plans, but daylight is not the same as sunshine. Keep your schedule flexible, carry lightweight waterproof protection and have indoor alternatives you would genuinely enjoy. Avoid committing the whole trip to weather-dependent activities. For a long-haul journey from London, that trade-off deserves thought: the warmth is dependable, while dry weather is not. September makes more sense if rain would change your plans without spoiling the holiday than if beach time is the main reason for travelling.