Koh Samui Weather in July
July in Koh Samui sees daytime temperatures around 30°C (86°F) and lows of 27°C (81°F) at night. With around 94 mm (3.7 in) of rainfall expected, it's worth packing a rain jacket.
Rainfall in Koh Samui in July
On average, there are about 17 days with rain during this month, averaging 94 mm (3.7 in). Neither particularly heavy nor particularly frequent, the rain this month is about average. A light jacket should be enough on most wet days.
Temperature in Koh Samui in July
Expect highs of 30°C (86°F) in Koh Samui in July, with nights dropping to around 27°C (81°F). The hottest part of the day is usually in the afternoon, so lighter clothing can help you stay comfortable. With overnight lows of 27°C (81°F), nights stay very warm. Air conditioning makes a real difference if you're sensitive to heat. A cold shower before bed can also help you get to sleep more comfortably.
Sunshine in Koh Samui in July
You can expect a moderate amount of sunlight, with approximately 156 hours. This means a pleasant mix of sun and overcast.
Average water temperature in July
At 29°C (84°F), the water feels bath-warm. Fine for swimming, but those looking for a cooling swim may be a bit disappointed.For Koh Samui itself, January and February generally stand out with the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Thailand, check out our Koh Samui's climate page.
Koh Samui Temperature in July
Min Temperature
27°C (81°F)
Max Temperature
30°C (86°F)
Water Temperature
29°C (84°F)
Chance of Rain
56%
Precipitation
94 mm (3.7 in)
Rainy days
17 days
Humidity
78%
Sunshine
156 hours
Percentage Sunshine
Daily Historical Temperatures
49-year average (1976-2025)
Based on our historical records, temperatures in Koh Samui typically stay consistent throughout July, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 26°C (79°F).
Average temperatures in July
Daily Historical Precipitation
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in July
Historical weather for Koh Samui in July
Browse day-by-day weather records for Koh Samui spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Koh Samui historical weather extremes in July
According to our 43 years of weather records for Koh Samui, the following extremes were recorded between 1982 and 2025.
- Koh Samui recorded its highest July temperature of 39°C (102°F) on July 31, 2010.
- On July 23, 1999, Koh Samui saw its coldest July day with temperatures maxing out at 27°C (81°F).
- Nighttime temperatures dropped to 20°C (68°F) on July 11, 2010, marking the coldest July night on record.
Best Places in Thailand in July
Find out more about the weather in Thailand and which places have the best travel conditions in this month. See all of Thailand in July →
perfect weather
pleasant
tolerable
unpleasant
poor
What to Wear in Koh Samui in July
Warm temperatures in July make for comfortable sightseeing weather. Pack breathable fabrics like cotton shirts, knee-length shorts or skirts, and comfortable walking shoes. A thin long sleeve for indoor spaces is handy. Prepare for significant rainfall with proper waterproof clothing and shoes. With water temperatures around 29°C (84°F), swimming conditions are excellent. Pack your swimsuit, goggles, and maybe some water shoes. It won't hurt to bring your sunglasses along, as you'll see some sunny periods.What To Do in Koh Samui in July
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Thailand, check out our Koh Samui's climate page.
Temperature Rainfall Sunshine Humidity Water Temp
See the full Koh Samui climate overview or explore weather in Thailand.
