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Ko Samui in January: Weather, Average temperature and Climate

Take a look at past year’s weather for Ko Samui in January and see if it is worth visiting.
Check flight prices to Ko Samui on Avionero:
January

Weather in Ko Samui in January 2025

Good Weather
Warm
🌧️
Rainy
🌊
Warm water
Are you considering a trip to Ko Samui in January? Well, the weather is usually on your side with an average maximum temperature of +77°F and about 3 sunny days. Just keep in mind that there may be some rain, with an average of 16 rainy days and 47 mm of precipitation. Expect good weather and pack accordingly to enjoy the outdoors. Search flights in one click on Avionero.
Good to know:
  • January is usually the coldest month of the year in Ko Samui;

Average weather

☀️
+77°F
Avg. max. temperature
+64°F
Min.
+86°F
Max.
47 mm
Total precipitation
79%
Avg. humidity
3 m/s
Avg. wind
3 ☀️
Sunny Days
11 ⛅️
Cloudy
16 🌦
Rainy
Our opinion: Ko Samui has good weather in January.

Average temperature in Ko Samui in January

Here are the expected maximum, average and minimum temperatures in Ko Samui for January based on the historical data.
Last Year
Historical Data

The temperature in January is +79°F on average, with a range between a maximum of +86°F during the day and a minimum of +64°F at night.

The average maximum temperature goes up 0% by the end of the month, compared with the beginning of the month, from +79°F to +79°F.

Is Ko Samui warm or cold in January?

Ko Samui is typically warm in January.

Maximum temperatures go down compared to the previous month from +79°F to +77°F. The minimum temperature also goes up from +75°F to +75°F.

It’s generally warm, but pack a long-sleeve shirt for evenings.

January is the coldest month in Ko Samui, here is the comparison with other months:

Water temperature in Ko Samui in January

Water in Ko Samui in January is Warm. It varies from +80°F to +83°F, with an average of +82°F. Note that the air temperature is lower than the water temperature, averaging around +77°F.

The water temperature in January is one of the coldest of the entire year:

The warmest water temperatures in Ko Samui are reached in May, when the average sea temperature rises to +86°F. The coldest water temperatures are in January, with an average of +82°F.

Can you swim in Ko Samui in January?

You can absolutely swim in Ko Samui in January, the water is warm (+82°F in average), similar to heated pools. Suitable for most people, including children and the elderly.
🦭
Cold
Below +61°F
🏄‍♂️
Fresh
61°F - 70°F
🏊
Comfortable
70°F - 77°F
👙
Warm
77°F - 82°F
🔥
Very warm
+82°C and up
Bring your swimming suit, sunscreen and your favorite inflatable pink flamingo.

Climate in Ko Samui in January

Ko Samui weather looks like this, on average, in January and the surrounding months.
DecemberJanuaryFebruary
Avg. temperature
+79°F+77°F+79°F
Min. temperature
+68°F+64°F+63°F
Max. temperature
+86°F+86°F+90°F
Rainfall
115 mm47 mm29 mm
Wind
3 m/s3 m/s3 m/s
Avg. water temperature
+83°F+82°F+82°F
Humidity
79%79%78%
Air pressure
1011 HPa1011 HPa1011 HPa
Sunny days
235
Cloudy days
101111
Rainy days
161611
Snowy days
000

January often has better weather than December. It’s getting colder in January. From +79°F in the day, the average maximum temperature lowers to +77°F. As January arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 115 mm to 47 mm. Humidity levels don’t change as the month goes on, averaging around 79%. The average wind speed doesn’t change much during January, staying around 3 m/s. The good news is there are likely to be more sunny days in January, from 2 to 3.

February brings much the same weather, it remains good.

Wind

Wind speed in Ko Samui in January based on historical data.
Last Year
Historical Data

The average wind speed is 2 m/s getting up to 5 m/s which is a light breeze; barely moving the tree leaves.

The average wind speed in Ko Samui is gradually decreasing during January, going from 4 m/s to 2 m/s over the course of the month.

Rain

Amount of rainfall in mm during January in Ko Samui based on historical data.
Last Year
Historical Data
A chance of rain on a typical day in January stands at 26%, leading to total precipitation of around 26 mm. The maximum amount of rainfall per day is around 10 mm, which is considered light rain. On average, there are about 8 rainy days during January, so prepare to bring an umbrella.
Here’s how January is compared with other months in the amount of precipitation, total mm:
Ko Samui wettest month is November, where a typical day has a 57% chance of precipitation and 278 mm of rainfall per day. February, on the other hand, is the driest month with a mere 38% chance of precipitation and 29 mm of rainfall per day.

How was the weather last January in Ko Samui?

This is the weather in Ko Samui in January 2023:
1 January
☀️
+78°F
2 January
☀️
+80°F
3 January
☀️
+81°F
4 January
☀️
+79°F
5 January
☀️
+80°F
6 January
🌧️
+80°F
7 January
☀️
+76°F
8 January
🌫️
+77°F
9 January
☀️
+77°F
10 January
☀️
+81°F
11 January
☀️
+78°F
12 January
☀️
+79°F
13 January
☀️
+80°F
14 January
☀️
+80°F
15 January
☀️
+85°F
16 January
☀️
+80°F
17 January
☀️
+80°F
18 January
☀️
+79°F
19 January
☀️
+80°F
20 January
☀️
+79°F
21 January
☀️
+80°F
22 January
☀️
+81°F
23 January
☀️
+81°F
24 January
☀️
+81°F
25 January
🌧️
+78°F
26 January
☀️
+78°F
27 January
☀️
+80°F
28 January
🌧️
+79°F
29 January
☁️
+80°F
30 January
🌫️
+76°F
31 January
☀️
+79°F
In January 2023 Ko Samui had 25 sunny days, 1 cloudy days, and 3 rainy days. The average maximum temperature was +79°F, with an absolute maximum of +86°F and a minimum of +75°F. The average humidity was 76%, with a maximum of 100% and a minimum of 49%. The average wind speed was 2 m/s, with a maximum of 9 m/s and a minimum of 0 m/s.
Are you planning a trip in January?

Climate Change Over the Years

This is how Ko Samui climate has changed over the last 43 years.

The climate in Ko Samui in January has not changed that much over the last 43 years.

The average temperature was the lowest in 1986 (+79°F) and the highest in 2012 (+83°F). The driest year was 1997 with only 927 mm of rainfall, and the wettest year was 1999 with 1981 mm.

FAQ

Frequently asked questions about the weather in Ko Samui in January:

Is January a good time to visit Ko Samui?

January is a really good time to go to Ko Samui. The weather is nice so plan your packing around outdoor activities and exploring. Check out other good time to visit Ko Samui.

Can you sunbathe in Ko Samui in January?

January is warm in Ko Samui. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.

Can you swim in Ko Samui in January?

Yes, you can swim in Ko Samui in January, the water temperature averaging at +82°F. This temperature is considered warm and comfortable for most swimmers.

Is Ko Samui rainy in January?

Ko Samui is usually dry in January. Plan your packing around outdoor activities and exploring.

Is it sunny in Ko Samui in January?

Usually, it’s not very sunny in Ko Samui in January, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.

Other cities in Thailand

Check out the weather for other cities in Thailand.

Monthly weather in Ko Samui

Source of the data

For this page, we’ve looked at the typical weather in Ko Samui, based on historical hourly weather data from January 1, 1979, to December 31, 2023.

For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.