January · Thailand weather
Thailand in January: Weather, What to Expect & Where to Go
Updated
January is the heart of Thailand's cool-dry season. Bangkok and the north are at their most comfortable, the Andaman coast is dry and bright, and only the Gulf islands are still shaking off late-monsoon swells.
Best region
North
Chiang Mai sits in the low-20s with crisp mornings and clear skies — the best month of the year up here.
Avoid
Gulf
Samui is technically dry but lingering northeast monsoon swells still bring choppy seas and grey days.
Good for
Cool mornings in Chiang Mai, beach weather on the Andaman side
January weather, region by region
Average temperatures and rainfall across Thailand's five climate regions in January. Tap the climate map on the homepage for an interactive month-by-month view.
| Region | Avg temp | Rainfall | Visit rating |
|---|---|---|---|
North Chiang Mai | 22°C | 10mm | Great |
Northeast Nakhon Ratchasima (Korat) | 24°C | 5mm | Great |
Central Bangkok | 27°C | 10mm | Great |
Andaman Phuket | 28°C | 35mm | Great |
Gulf Koh Samui | 27°C | 55mm | Great |
City spotlights
One city per region — what January actually feels like on the ground, and what to do or skip.
North
Chiang Mai
By the numbers
Chiang Mai averages 22°C in January — daytime highs around 28°C, nights dipping to 14–17°C. Just 10mm of rain across 1–2 wet days, and humidity sits at its yearly low of around 60%.
The only month it ever feels properly cold in Thailand. Locals wear puffer jackets at dawn; in the mountains around Pai and Mae Hong Son, valley temperatures can drop below 10°C before sunrise.
Cool mornings, warm afternoons, almost no rain. Bring a light jacket for sunrise at Doi Suthep and early-morning markets — temperatures can dip below 15°C in the hills.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Northeast
Nakhon Ratchasima (Korat)
By the numbers
The Korat plateau averages 24°C, with daytime highs around 30°C and cool nights of 15–18°C. Rainfall is negligible — about 5mm spread over 1 wet day for the whole month.
Dry, dusty, and quiet. Khao Yai mornings are genuinely cold by Thai standards — you can see your breath at viewpoints before 7am.
Cool, dry, and quiet. The Korat plateau sits at altitude, so early mornings can dip below 15°C — ideal for Phimai Historical Park and day trips up to Khao Yai National Park.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Central
Bangkok
By the numbers
Bangkok averages 27°C — daytime highs around 32°C, nights around 22°C. Rainfall is minimal (about 10mm across 1–2 days) and humidity drops to around 55%, the most comfortable level of the year.
Bangkok at its most walkable. You can do an afternoon at Chatuchak Market or a temple loop without ending up soaked through.
About as good as Bangkok ever gets — temperatures hover around 27°C with low humidity. Markets, walking tours, and rooftop bars all comfortable.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Andaman
Phuket
By the numbers
Phuket averages 28°C with consistently bright days. Around 35mm of rain across 3–4 wet days — most fall as brief overnight showers. Sea temperatures sit around 28°C.
Peak Andaman season. Long-tail boats run every morning, water visibility on Similan and Phi Phi diving hits 20–30m, and beach days are reliably sunny.
Peak season for the Andaman side. Calm seas, dry days, and packed beaches — book hotels well in advance and expect peak pricing.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Gulf
Koh Samui
By the numbers
Koh Samui averages 27°C but still sees around 55mm of rain across 6–8 wet days. The northeast monsoon is fading but not gone — seas remain choppy.
Looks okay on paper, feels grey in practice. Mornings are often overcast, afternoon rain is common, and the swell makes long-tail trips to Koh Tao or Angthong dicey.
The driest of the wet months, but lingering swells and grey mornings can still spoil a beach week. Pick Phuket or Krabi instead if you've only got January.
Year-round climate
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Events & festivals in January
New Year's hangover
The post-NYE crowd thins out around the second week — wait until then for cheaper flights and quieter beaches.
Where to actually go
Ten days in January
- 3days
Bangkok
Cool, dry, walkable — the best month of the year for the city.
Train · 13h overnight sleeperBook on 12Go - 3days
Chiang Mai
Crisp mornings, clear mountains. Day trips to Doi Suthep and Doi Inthanon.
Flight · 1h 30mBook on 12Go - 4days
Krabi
Andaman at its peak — Railay, Phi Phi day trips, calm seas for diving.
Skip the Gulf islands this month — Samui, Phangan, and Tao are still in their wet pattern. Save them for May–August.
Sea conditions in January
Thailand has two coastlines on opposite monsoon calendars. Here's what each looks like this month for swimming, diving, and boat trips.
Andaman coast — Phuket, Krabi, Phi Phi
Calm and clear. Diving visibility around the Similan Islands hits 20–30m, and Phi Phi day trips run on flat seas every day. Sea temperature ~28°C.
Gulf coast — Samui, Phangan, Tao
Choppy and grey. Lingering northeast monsoon swells make beach days hit-or-miss on Samui and Phangan; Koh Tao dive boats run but visibility is poor by Gulf standards.
How crowded is Thailand in January?
Peak high season. Book Phuket and Krabi 2–3 months out, Chiang Mai 4–6 weeks ahead. The first 10 days of January carry NYE-tail pricing; the post-13th lull is the cheapest window of the month.
What to pack for Thailand in January
- Light layers — T-shirts plus one long-sleeve for north evenings
- A real fleece or light jacket if you're going to Chiang Mai, Pai, or Mae Hong Son
- Modest temple-visit outfit (shoulders and knees covered)
- SPF 30+ sunscreen for the Andaman side
- A compact rain jacket only if you're heading to Koh Samui
January is the one month of the year you actually need warm clothing for Thailand. If you're staying on a mountain in Pai or doing sunrise at Doi Suthep, single-digit temperatures are possible — pack heavier than your instincts say.
Thailand in January — common questions
Is January a good time to visit Thailand?
Yes — January is one of the two or three best weather months of the year, alongside February and November. The trade-off is peak-season pricing (especially the first 10 days) and busy beaches on the Andaman coast. The only region to avoid is the Gulf islands, which are still in their wet pattern.
Is it rainy season in Thailand in January?
No. January sits in the heart of Thailand's cool-dry season for most of the country. Bangkok, Chiang Mai, and the Andaman coast (Phuket, Krabi) see almost no rain — typically under 35mm across 1–4 days for the whole month. The only exception is the Gulf islands (Koh Samui, Phangan, Tao), which are still recovering from the northeast monsoon.
How hot is Bangkok in January?
Bangkok averages 27°C in January, with afternoon highs around 32°C and overnight lows around 22°C. Humidity drops to about 55% — its lowest of the year — which makes the heat noticeably more comfortable than the same temperatures in April or May.
Can you swim in Phuket in January?
Yes — January is peak swimming and diving season on the Andaman coast. Sea temperatures hold around 28°C, visibility for diving runs 20–30m around the Similan and Phi Phi islands, and long-tail boat trips run every day. Expect crowded beaches on Patong, Karon, and Railay.
Should I avoid Koh Samui in January?
Don't write it off, but understand the trade-off. The Gulf islands are on a flipped weather calendar — January is the tail end of their wet season, so expect grey mornings, choppy seas, and occasional washout days. If guaranteed sunshine is the priority, choose Phuket or Krabi for a January trip and save Samui for May–August.
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