Weather in St Lucia in December

How December compares

December is the 10th warmest month of the year in St Lucia and ranks 21st of 134 destinations we compare for December - see where else is hot in December. Against London's average high of 7.7°C in December, St Lucia is 19.8°C warmer by day and 21.3°C warmer at night.

Daytime and night-time in December

The typical December day in St Lucia peaks at 27.5°C, but that is an average: the warmest 10% of days reach 28.5°C or more. About 100% of days top 25°C. Nights average 24.0°C; one night in ten drops to 23.0°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest December day here reached 29.6°C (2019-12-25) and the coldest night 20.9°C (2017-12-12).

Rain in December

Wet (more than 8 rainy days): about 14 days with 1 mm or more, 46 mm in total. Year to year it varies a lot - the wettest December was 1998 with 129 mm, the driest 2014 with 15 mm. Humidity averages 76%.

Sea temperature in December

The sea averages 27.7°C - warm enough to swim (22°c+). Depending on the year it ranges from 27.2°C to 28.0°C. For the warmest sea here, come in September (29.0°C).

Sunshine and daylight

Around 6.4 hours of sunshine a day (estimated from cloud cover), 11.2 hours of daylight: the sun rises about 06:20 and sets about 17:38 local time in mid-December. Average cloud cover is 42%.

Is December a good time to visit St Lucia?

It is a reasonable choice: hot days but expect showers. The best months for St Lucia on our scoring are February, March, January; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Hot days, warm evenings and comfortable swimming

The warmth is a substantial change from London, where December daytime highs average 7.7°C. St Lucia's 27.5°C average high is hot enough for light summer clothing, while 76% humidity can make walking around feel sticky. Keep more active plans for the cooler parts of the day and leave room for shade at midday. The sea averages 27.7°C, making swimming an appealing part of a December trip rather than something to brace yourself for. Evenings offer limited relief from the warmth, with average lows of 24°C. Breathable clothes are more useful than heavy layers, and comfortable sleeping conditions are worth considering when choosing accommodation.

Allow for rain rather than expecting constant sun

December is a wet-weather compromise: about 14 days have measurable rain, so an entirely dry trip is not a sensible expectation. That does not mean every wet day is a washout, but the monthly figures cannot tell you when rain will arrive or how long it will last. A light waterproof and plans you can rearrange are sensible. There are about 6.4 hours of sunshine within 11.2 hours of daylight, leaving plenty of scope for time outdoors without promising clear skies throughout. December suits travellers who value warmth and swimming more than dry-weather certainty. If your timing is flexible, January, February and March rate better overall.