Where is it warm in December? The dry-season shortlist

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December is the first month where the weather question is easy and the price question is hard.

Hurricane season closed on November 30. Mexico’s Pacific dry season is established. The Caribbean is reliably warm. Almost everywhere on the shortlist below is going to give you the weather you want.

What December actually decides is how much you pay for it — and the answer depends less on where you go than on which half of the month you go in.

The two Decembers

There are effectively two separate months here:

December 1–14. Low-to-shoulder season pricing in most of the Caribbean and Mexico. Excellent weather. Quiet. This is one of the best value windows of the entire winter.
December 15–31. The single most expensive travel window on the calendar. Expect 40–60% above the first-half numbers for identical rooms.

If your dates are flexible at all, that gap is the biggest lever available to you — bigger than destination choice, bigger than hotel tier, bigger than any booking hack.

The shortlist

Destination	Typical high	Rain risk	Est. week for two (early Dec)	The honest note
Curaçao	84°F	Very low	$2,000	Outside the hurricane belt, milder holiday price step than Aruba
Costa Rica (Guanacaste)	90°F	Very low	$1,900	Dry season fully established. Hottest option here
Belize	82°F	Very low	$1,900	Dry season starts in earnest. English-speaking
Puerto Vallarta, MX	82°F	Very low	$1,400	Whale season begins. Excellent value early in the month
Cabo San Lucas, MX	76°F	Very low	$1,800	Driest of the lot. Sea is cooling
Aruba	84°F	Very low	$2,300	Most reliable weather, steepest holiday premium
Oaxaca coast, MX	86°F	Very low	$1,250	Cheapest genuinely hot option. Harder to reach
Phoenix, AZ	66°F	Very low	$1,000	No passport. Warm days, cold nights
Puerto Rico	83°F	Low	$1,600	No passport. Prices climb fast after the 15th
Panama (Bocas)	85°F	Moderate	$1,700	Cheap and beautiful. Rain is a real gamble

Researched estimates for two people, seven nights, mid-range, from a mid-US hub, checked August 2026. First-half-of-December pricing. Verify your own dates.

What December does to the water

Worth knowing, because it catches people out: air temperature and sea temperature aren’t the same season.

The sea lags the air by roughly a month. In December that mostly works in your favor in the Caribbean — the water is still holding late-autumn warmth. But on Mexico’s Pacific side, particularly around Cabo, the sea is noticeably cooler than the air suggests, and by late December it’s brisk.

If swimming in the ocean is the actual point of your trip, weight the Caribbean side over the Pacific side in December.

The holiday-week question

If you’re locked into December 20–January 2 — school calendars, family, work — you’re buying at peak and there’s no trick that changes that. What you can do is change what you’re buying:

Go somewhere with thinner demand. Curaçao’s holiday step is milder than Aruba’s. Mazatlán’s is milder than Cabo’s. Bocas del Toro barely has one.
Book an apartment rather than a resort. The holiday premium tends to be steeper on resort inventory than on private rentals.
Consider the week after New Year. January 2–10 is one of the sharpest price drops on the calendar — the same weather, a fraction of the cost, and almost nobody there.

That last one is the genuinely useful move if you have any flexibility on which week the trip happens.

When to book December

If you’re reading this in August or September, book now. Holiday premiums load progressively and early-loaded fares on most routes are meaningfully cheaper.

If you’re reading this in November for December, go somewhere less obvious and book accommodation with free cancellation so you can rebook if a better price appears.