Weather in Key West in December

Prime time. If you get to pick your dates, December is the one. Highs average 24.1 °C, lows 22.6 °C, and rain falls on 7 days — nothing in the month is working against you.

December ranks 5 of 12 in Key West: past the worst of the year but short of January, which is the month to book if the dates are open.

Rain on 7 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average December reaches 30 °C; the day barely swings — 1.5 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 27.1 °C and the coldest night fell to 13.8 °C, and the wettest single day dropped 37 mm — roughly 95% of the month's rain in one day.

December is moderately variable: 2 mm in the driest year against 112 mm in the wettest, around an average of 39 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind sits around 18.9 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 79%, high enough to notice on the warm days without dominating them.

How December sits in the year

Temperatures hold steady either side: 25.6 °C in November, 24.1 here, 22.7 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of Key West's year — 10.6 hours of daylight against 13.6 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 26 °C in December — warm enough to stay in as long as you like. The sea peaks at 29.9 °C in August and bottoms out at 24.9 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in Key West versus nearby

If Key West is one option among several, the nearby comparison is worth making. Miami is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Cape Coral is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: December is effectively as good as it gets here — 4 points behind January, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Key West

See all twelve months in Key West, or where else to go in December.