Guanacaste weather in December
Guanacaste averages 31°C by day and 24°C at night in December, with the sea at 29°C and about 37 mm of rain in the month. That is about 2°C warmer than November.
Day
31°C
Night
24°C
Sea
29°C
Rain
37 mm
Flight from London
11h
What December feels like
December is hot in Guanacaste: proper beach weather.
The sea is warm at 29°C: comfortable for long swims.
Rain is occasional: about 37 mm in the month.
That is 22°C warmer than an average December day in London.
Of the 56 sun destinations we track, Guanacaste is the #4 warmest in December.
Want it warmer in December?
These are hotter than Guanacaste this month for at most an hour and a half more flying:
Guanacaste weather by month
December is highlighted. Compare with November and January, or see the full year in Guanacaste.
| Month | Day | Night | Sea | Rain |
|---|---|---|---|---|
| January | 32°C | 25°C | 28°C | 14 mm |
| February | 34°C | 25°C | 28°C | 6 mm |
| March | 34°C | 25°C | 29°C | 15 mm |
| April | 34°C | 26°C | 30°C | 70 mm |
| May | 31°C | 25°C | 30°C | 267 mm |
| June | 29°C | 24°C | 30°C | 379 mm |
| July | 30°C | 25°C | 30°C | 240 mm |
| August | 30°C | 24°C | 30°C | 295 mm |
| September | 29°C | 24°C | 30°C | 346 mm |
| October | 29°C | 24°C | 29°C | 502 mm |
| November | 29°C | 24°C | 28°C | 214 mm |
| December | 31°C | 24°C | 29°C | 37 mm |
Guanacaste in December: quick answers
Is Guanacaste hot in December?
December is hot in Guanacaste: proper beach weather. Average highs are 31°C and lows 24°C.
Can you swim in Guanacaste in December?
The sea is warm at 29°C: comfortable for long swims.
Does it rain in Guanacaste in December?
Rain is occasional: about 37 mm in the month.
What is the warmest month in Guanacaste?
March, at an average high of 34°C. The coolest is October at 29°C.
How long is the flight to Guanacaste from the UK?
About 11h direct from London, estimated from the 8,795 km distance. Check your airline for exact times.
Still choosing? See where is hot in December for every destination ranked by temperature, sea and flight time.
How we measured this
Averages of every day in December from 2016 to 2025, from the Open-Meteo historical weather archive (ECMWF ERA5 reanalysis). Sea temperature is the 2023 to 2025 average from the Open-Meteo marine archive. Rain is the average monthly total. Reanalysis describes an area about 25 km across, so sheltered resorts can run a degree or two warmer. Flight time is a distance-based estimate from London Heathrow.
Planning Guanacaste in December?
Save the restaurants, beaches and views you find on TikTok and Instagram for Guanacaste straight to a map, then let Dream Trip turn them into a day-by-day plan.
