You're standing on Patong Beach. It is December 15th. You expected a cooling breeze, but instead, you feel that unmistakable Thai humidity clinging to your skin like a damp towel. Most travel brochures lie to you. They paint this picture of "cool" tropical winters that make it sound like you’ll need a sweater for your sunset dinner. You won't. Honestly, the temperature of Phuket in December is arguably the most misunderstood metric in Southeast Asian travel.
It’s hot. Not "melting pavement" April hot, but definitely "I need a third shower today" hot.
December marks the sweet spot of the "Dry Season," or what the Thai Meteorological Department calls the Northeast Monsoon. This isn't a monsoon of rain, but a monsoon of wind. It blows in from China, stripping the moisture out of the air—mostly. You’ll see the thermometer hovering around 31°C (88°F) during the day. It sounds manageable until you factor in the UV index, which frequently hits 11+. That is "extreme" territory. If you aren't careful, you’ll be the color of a boiled lobster before your first Chang beer is finished.
Why the Temperature of Phuket in December Feels Different
Humidity is the silent killer of comfort. In October, the humidity in Phuket can sit at a suffocating 90%. By December, it drops to a much more tolerable 70% or 75%. That 15% difference is why everyone flocks here. It’s the difference between feeling like you’re breathing through a warm sponge and actually enjoying a walk down Bangla Road.
Nighttime is where the magic happens.
When the sun dips behind the Andaman Sea around 6:00 PM, the temperature of Phuket in December slides down to a delightful 24°C (75°F). This is peak Phuket. You can sit outside at a night market in Phuket Town, eating spicy moo ping, without sweat dripping into your eyes. It’s the only time of year when the air feels crisp-ish. If you head up to the Big Buddha or into the hills of Kathu, it might even feel—dare I say—chilly to a local.
Rain is a Ghost (Usually)
Statistically, December is one of the driest months. You’re looking at maybe 40mm to 60mm of rain for the entire month. Compare that to the 400mm you’d get in September.
But don't be fooled into thinking it's a total desert.
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Phuket is an island. It makes its own rules. You might get a "Christmas Wash," a sudden, violent downpour that lasts exactly twenty minutes and then vanishes, leaving the air smelling like wet jasmine and hot asphalt. These little bursts are actually a relief. They knock the dust off the palm trees and temporarily drop the temperature by five degrees.
I’ve seen tourists panic when they see a gray cloud over the Phi Phi Islands. Don't. It’ll pass before you can finish your mango sticky rice.
Sea Temperatures: The Bathwater Effect
If you’re planning on diving or snorkeling at the Similan Islands—which, by the way, are only open during this window—the water is perfect. We’re talking 29°C (84°F).
It’s basically bathwater.
You don't need a thick wetsuit. A rash guard is plenty. The water is at its most transparent this month because the winds are consistent and the sediment has settled. It’s the kind of blue that looks fake in photos. If you go to Kata Noi or Nai Harn, the waves are minimal, making it the safest time for kids to splash around without getting clobbered by a rogue monsoon swell.
The Reality of the "Cool" Season
Locals call this "winter." It’s hilarious. You’ll see Thai motorbike riders wearing North Face jackets when it hits 23°C. For someone flying in from London or New York, it’s a heatwave.
The heat is constant.
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One thing people get wrong is the sun's intensity. Because the air is slightly drier, the sun feels "sharper" on your skin. There’s less cloud cover to act as a filter. I’ve seen seasoned travelers get heat exhaustion because they thought the "lower" temperature of Phuket in December meant they didn't need to hydrate as much. Huge mistake. You need to be drinking double the water you think you need. Electrolyte packets from the local 7-Eleven (look for the "Royal-D" brand) are your best friend.
Packing for 31 Degrees
Forget the jeans. Seriously. Unless you’re planning on spending your entire trip in a high-end mall like Central Floresta where the AC is set to "Arctic," denim is a prison sentence.
- Linen is king. It breathes. It dries fast.
- Loose cotton. Anything tight will result in heat rash.
- The "Evening Layer." A very light hoodie or a pashmina is only necessary if you’re taking a long-distance bus or a ferry, as they crank the air conditioning to unbearable levels.
- Footwear. Flip-flops (thongs) are the island uniform, but if you're walking the hilly streets of Patong, get some breathable mesh sneakers.
Understanding the Microclimates
Phuket isn't just one flat slab of land. The temperature of Phuket in December varies depending on where you're standing.
If you’re on the west coast (Bang Tao, Kamala, Surin), you get the direct sea breeze. It’s refreshing. If you’re in the center of the island, like Thalang or near the Heroines' Monument, the heat gets trapped by the vegetation and the hills. It feels five degrees hotter there because the air is stagnant.
Then there’s the "Urbant Heat Island" effect in Patong. Between the concrete, the thousands of motorbikes, and the massive AC units pumping hot air into the alleys, Patong can feel significantly more sweltering than a quiet beach like Layan. If you’re sensitive to heat, stay as close to the shoreline as possible.
The Crowds vs. The Climate
There is a direct correlation between the perfect weather and the number of people. December is "Peak-Peak" season.
Prices for villas in Rawai or apartments in Karon skyrocket. The beaches are packed. Why? Because everyone wants that guaranteed sunshine. While the temperature of Phuket in December is arguably the best of the year, you pay for it in "people-density."
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If you want the weather without the madness, try to arrive in the first week of December. Once December 20th hits, the "Festive Season" kicks in, and the island reaches its carrying capacity. Traffic becomes a nightmare. A trip from the airport to Chalong that usually takes 45 minutes can easily take two hours in the December heat. Sitting in a taxi while the sun beats down on the roof is the only time the December weather feels like a burden.
Practical Advice for Your December Visit
Don't overschedule. The heat, even at its "coolest" in December, will drain your battery.
Plan your outings for the early morning—think 7:00 AM to 10:00 AM. This is when the light is best for photos and the temperature of Phuket in December is at its most forgiving. Spend the midday hours (12:00 PM to 3:30 PM) in the shade, in the pool, or taking a nap. Thai culture has a slow pace for a reason; fighting the tropical sun is a losing battle.
By 4:00 PM, the intensity breaks. This is the golden hour. The sky turns a soft lilac, the breeze picks up, and the island comes alive again.
Actionable Steps for Navigating Phuket's December Weather:
- Check the UV Index Daily: Use a reliable app like WeatherUndeiground or Windy. If it says 10+, stay under an umbrella.
- Hydrate with Purpose: Don't just drink water. Drink coconut water. The natural potassium helps your body retain fluids better in the humidity.
- Book Air-Conditioned Transport: If you're traveling long distances across the island, spend the extra 200 baht for a private Bolt or Grab car rather than a tuk-tuk. The breeze in an open-air tuk-tuk is just hot air blowing in your face.
- Sunscreen Choice: Buy "Reef Safe" sunscreen if you're going into the ocean. The December sun is brutal, but the chemicals in standard sunscreens are destroying the coral at places like Freedom Beach.
- Timing the Big Buddha: If you want to see the Big Buddha, go at 6:30 AM. You’ll beat the tour buses, and the air at the top of the mountain will actually be cool enough to enjoy the view.
The temperature of Phuket in December is exactly why this island became a global phenomenon. It’s reliable. It’s predictable. It’s the closest thing to a "perfect" tropical climate you can find, provided you respect the sun and don't expect the "cool season" to be anything other than a slightly less sweaty version of paradise. Pack light, stay hydrated, and accept that you will be glowing (mostly from sweat) for the duration of your stay.
Next Steps for Your Trip:
- Download the Grab or Bolt app now to ensure you have access to air-conditioned transport at fair prices.
- Purchase high-quality, SPF 50+ mineral-based sunscreen before you arrive, as imported brands are significantly more expensive in Thai pharmacies like Boots or Watsons.
- If you're sensitive to heat, look for accommodation specifically in the Cape Panwa or Nai Harn areas, where the geography allows for better cross-breezes than the central valleys.