San José weather in December
In December, San José has daytime highs averaging 24 °C, nights around 17 °C, with 17 wet days. Figures are 1991–2020 climate normals.
- 23.7°C Average high
- 17.1°C Average low
- 17days Wet days
- 163mm Rainfall
- 12h Daylight
Daily temperatures through December
How December develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 December | 23.5 °C | 17.2 °C | 62 % |
| 11–20 December | 23.6 °C | 17.0 °C | 53 % |
| 21–31 December | 23.9 °C | 17.0 °C | 48 % |
- Rain is most likely over days 1–10 of December (62 % of days) and least likely over days 21–31 (48 %).
What to expect
| Measure | Typical December | Share of the month |
|---|---|---|
| Days above 25 °C | 4.3 of 31 | 14 % |
| Days above 30 °C | 0 of 31 | 0 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 17 of 31 | 54 % |
Conditions in December
| Measure | Average |
|---|---|
| Mean temperature | 20 °C |
| Record high (1991–2020) | 27 °C |
| Record low (1991–2020) | 13 °C |
| Relative humidity | 84 % |
| Wind speed | 11 km/h |
| Cloud cover | 63 % |
December compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 24.5 °C | 95 mm | 53 % |
| February | 25.5 °C | 66 mm | 49 % |
| October | 23.6 °C | 432 mm | 91 % |
| November | 23.3 °C | 319 mm | 84 % |
| December | 23.7 °C | 163 mm | 63 % |
See all twelve months for San José
- December is the 10th warmest month here.
- It is the 5th driest month of the year.
- It ranks 4th for least cloud cover.
- Days last about 12 hours from sunrise to sunset.
- It rains on 17 of 31 days — 54 % of the month.
- Nights are about 6.7 °C cooler than the middle of the day.
- The hottest December day on record since 1991 reached 27 °C, 3.6 °C above the usual daytime high.
QuestionsDecember in San José, answered
How warm is San José in December?
Daily highs average 24 °C and nights fall to about 17 °C, a spread of 6.7 °C between afternoon and dawn. That makes December the 12th warmest month of the year here.
Does it rain much in San José in December?
December averages 163 mm of rain, spread over about 17 of the 31 days — 54 % of the month. Cloud cover averages 63 % of the sky.
How long are the days in December?
San José averages 12 hours between sunrise and sunset in December. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.