Weather in St Lucia in May

How May compares

May is the 2nd warmest month of the year in St Lucia and ranks 24th of 134 destinations we compare for May - see where else is hot in May. Against London's average high of 16.6°C in May, St Lucia is 12.5°C warmer by day and 16.5°C warmer at night.

Daytime and night-time in May

The typical May day in St Lucia peaks at 29.1°C, but that is an average: the warmest 10% of days reach 30.1°C or more. About 100% of days top 25°C and 1 in 7 pass 30°C. Nights average 24.8°C; one night in ten drops to 23.9°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest May day here reached 31.3°C (2005-05-22) and the coldest night 22.6°C (2018-05-19).

Rain in May

Wet (more than 8 rainy days): about 13 days with 1 mm or more, 51 mm in total. Year to year it varies a lot - the wettest May was 2012 with 157 mm, the driest 2015 with 12 mm. Humidity averages 74%.

Sea temperature in May

The sea averages 27.6°C - warm enough to swim (22°c+). Depending on the year it ranges from 27.2°C to 28.1°C. For the warmest sea here, come in September (29.0°C).

Sunshine and daylight

Around 5.2 hours of sunshine a day (estimated from cloud cover), 12.7 hours of daylight: the sun rises about 05:37 and sets about 18:24 local time in mid-May. Average cloud cover is 59%.

Is May 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, with little cooling after dark

Average daytime highs of 29.1°C come with 74% humidity, so plan for heat that can feel sticky rather than dry. May is among St Lucia's warmest months, and every day reaches 25°C. You do not need exceptional temperatures to find the midday warmth tiring: light, loose clothing, shade and regular drinks are sensible priorities. Keep more active plans for the cooler parts of the day rather than pushing through lunchtime. Nights average 24.8°C, so evenings are still warm enough for light clothing. If you struggle to sleep in the heat, prioritise accommodation with effective cooling.

Allow for rain rather than expecting clear skies

Rain is the main catch in May, with about 13 days receiving measurable rainfall. That is enough to make rigid outdoor plans less appealing, but it does not mean those days are complete washouts. There is about 5.2 hours of sunshine within 12.7 hours of daylight, so expect a mix rather than clear skies throughout. The figures do not tell you when rain will fall, so do not build your plans around an assumed dry morning or wet afternoon. Pack a light waterproof and keep room to change plans. May suits travellers who can enjoy the warmth without needing constant sunshine.

A warm sea makes swimming a strong reason to go

The sea averages 27.6°C, making swimming a strong point of a May trip. Its year-to-year range of 27°C to 28°C suggests little variation in water temperature, though warm water alone does not establish safe swimming conditions. For someone who dislikes a chilly dip, this is a clear advantage. Pack swimwear alongside sun protection, and leave yourself the option of swimming when conditions suit rather than fixing every outing in advance. With a flight from London of about 9 h 12 min, May makes most sense if sustained warmth and comfortable water temperatures justify the long-haul journey for you.