Weather in Guanacaste in January

How January compares

January is the 5th warmest month of the year in Guanacaste and ranks 8th of 134 destinations we compare for January - see where else is hot in January. Against London's average high of 7.4°C in January, Guanacaste is 22.6°C warmer by day and 20.2°C warmer at night.

Daytime and night-time in January

The typical January day in Guanacaste peaks at 30.0°C, but that is an average: the warmest 10% of days reach 31.8°C or more. About 100% of days top 25°C and 1 in 2 pass 30°C. Nights average 22.4°C; one night in ten drops to 21.2°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest January day here reached 35.6°C (2019-01-27) and the coldest night 19.3°C (1997-01-10).

Rain in January

Dry (3 rainy days or fewer): about 1 days with 1 mm or more, 3 mm in total. Year to year it varies a lot - the wettest January was 1993 with 23 mm, the driest 1992 with 0 mm. Humidity averages 70%.

Sea temperature in January

The sea averages 27.0°C - warm enough to swim (22°c+). Depending on the year it ranges from 26.3°C to 27.6°C. For the warmest sea here, come in May (28.9°C).

Sunshine and daylight

Around 7.8 hours of sunshine a day (estimated from cloud cover), 11.4 hours of daylight: the sun rises about 06:04 and sets about 17:38 local time in mid-January. Average cloud cover is 32%.

Is January a good time to visit Guanacaste?

Yes - it is one of the better months: hot days, little rain and long sunny days. The best months for Guanacaste on our scoring are February, January, December; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Hot days, with little need for warm evening clothes

Expect to dress for heat throughout your stay, not just on the sunniest afternoons. Every January day reaches 25°C in the figures, while 51% reach 30°C. The hotter days can reach around 32°C or more, so plan anything energetic for earlier in the day and leave room for shade at midday. Humidity averages 70%, which can make activity feel more tiring than the temperature alone suggests. Loose, breathable clothes are the practical choice. With average night lows of 22.4°C, evenings usually remain warm; if you rely on cool nights to sleep comfortably, consider accommodation with air conditioning.

Very little rain, but not sunshine all day

January is a dry month, with about 1 rainy day, so rain is unlikely to be the main constraint on your plans. You can reasonably organise your holiday around time outdoors without making wet-weather alternatives the priority. There are about 7.8 hours of sunshine within 11.4 hours of daylight, though that does not mean every daylight hour will be sunny. The more useful preparation is sun protection: pack sunscreen, sunglasses and a hat, and choose somewhere you can sit in shade. For travellers who dislike humid heat, the lack of rain does not make this a cool or gentle month.

Warm water makes this a good month for swimming

The sea averages 27°C in January, with a year-to-year range of 26°C to 28°C. That makes it a comfortable prospect for travellers who find cooler seas off-putting, rather than something to brave briefly before heading back to shore. A holiday built around swimming and resting in the shade fits these conditions well. Bear in mind that warm water may offer less of a cooling contrast than you expect after sitting in the heat. Sea temperature also tells you nothing about local currents or conditions on the day, so follow local safety advice rather than treating warmth as a sign that swimming is safe.