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Monthly climate in San Juan, Alajuela, Costa Rica

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification San Juan features a tropical monsoon climate (Am).Temperatures typically range between 20 °C (68 °F) and 21 °C (70 °F) through the year, but rarely can drop to 13 °C (56 °F) or can rise to as high as 29 °C (85 °F).The average annual precipitation amounts to about 2722 mm (107.2 inches) and receives 222 rainy days on the 1 mm (0.04 inches) threshold annually.San Juan enjoys an average of 3018 hours of sunshine throughout the year, and daylight varies from 11 hours 32 minutes to 12 hours 41 minutes per day.

Monthly average temperatures in San Juan, Alajuela, Costa Rica §

The warmest months in San Juan are April, May and June, with daily mean temperatures ranging from 21 to 21 °C (70 - 70 °F) throughout the day. The coldest temperatures usually occur in January, October and December, when daily mean temperatures range from 20 to 20 °C (68 - 68 °F) throughout the day. On average each year, San Juan experiences 142 days above 25 °C (77.0 °F) and 0 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in San Juan, Alajuela, Costa Rica.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 27°C
(82°F)		 28°C
(83°F)		 28°C
(83°F)		 29°C
(85°F)		 28°C
(83°F)		 27°C
(81°F)		 27°C
(81°F)		 28°C
(82°F)		 27°C
(80°F)		 27°C
(80°F)		 26°C
(79°F)		 26°C
(80°F)
Mean maximum 26°C
(80°F)		 27°C
(81°F)		 27°C
(82°F)		 28°C
(83°F)		 27°C
(80°F)		 26°C
(80°F)		 27°C
(80°F)		 27°C
(80°F)		 26°C
(79°F)		 26°C
(79°F)		 26°C
(79°F)		 26°C
(79°F)
Average high 24°C
(76°F)		 25°C
(78°F)		 26°C
(79°F)		 26°C
(79°F)		 25°C
(77°F)		 25°C
(77°F)		 25°C
(76°F)		 25°C
(76°F)		 25°C
(76°F)		 24°C
(75°F)		 24°C
(75°F)		 24°C
(76°F)
Daily mean 20°C
(68°F)		 20°C
(69°F)		 21°C
(70°F)		 21°C
(70°F)		 21°C
(70°F)		 21°C
(70°F)		 21°C
(69°F)		 20°C
(69°F)		 20°C
(69°F)		 20°C
(68°F)		 20°C
(68°F)		 20°C
(68°F)
Average low 16°C
(62°F)		 16°C
(62°F)		 17°C
(62°F)		 18°C
(64°F)		 18°C
(65°F)		 18°C
(65°F)		 18°C
(65°F)		 18°C
(64°F)		 17°C
(64°F)		 17°C
(64°F)		 17°C
(64°F)		 17°C
(63°F)
Mean minimum 14°C
(58°F)		 14°C
(58°F)		 15°C
(59°F)		 16°C
(60°F)		 17°C
(62°F)		 17°C
(63°F)		 16°C
(62°F)		 16°C
(61°F)		 16°C
(61°F)		 16°C
(61°F)		 16°C
(60°F)		 15°C
(59°F)
Minimum 13°C
(56°F)		 13°C
(56°F)		 14°C
(57°F)		 15°C
(58°F)		 16°C
(61°F)		 16°C
(60°F)		 16°C
(61°F)		 16°C
(60°F)		 15°C
(60°F)		 15°C
(60°F)		 15°C
(59°F)		 15°C
(58°F)

Compare climate in San Juan with other places

Compare temperature, precipitation, sunshine, UV index in San Juan, Alajuela, Costa Rica with other places around the world.

Monthly average precipitation in San Juan, Alajuela, Costa Rica §

San Juan usually has the most precipitation in May, September and October, with an average of 28 rainy days and 466 mm (18.3 inches) of precipitation per month.The driest months in San Juan are January, February and March. On average, 20 mm (0.8 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in San Juan, Alajuela, Costa Rica.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 32 (1.3) 13 (0.5) 15 (0.6) 79 (3.1) 391 (15.4) 351 (13.8) 233 (9.2) 331 (13.0) 436 (17.2) 570 (22.4) 209 (8.2) 63 (2.5)
Average precipitation days (≥ 1 mm) 6 3 4 16 27 27 26 26 28 29 19 11

Monthly sunshine hours in San Juan, Alajuela, Costa Rica §

The sunniest months in San Juan are February, March and April, when the sun shines an average of 10 hours 16 minutes a day.Least sunny months in San Juan: July, August and October receive an average of 6 hours 48 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in San Juan, Alajuela, Costa Rica.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 249 296 328 299 235 226 209 213 229 210 229 291
Mean daily daylight hours 11h 35m 11h 47m 12h 3m 12h 20m 12h 34m 12h 41m 12h 37m 12h 25m 12h 9m 11h 52m 11h 38m 11h 32m

Solar UV radiation in San Juan, Alajuela, Costa Rica §

San Juan experiences the highest level of ultraviolet (UV) radiation in March, April and May, when the maximum UV index can reach values of 14 - 15, which corresponds to the Extreme category of sun exposure.January, November and December are in the Very High / Extreme exposure category. In these months, the maximum values of the UV index do not exceed 12. For more detailed information, check out our hourly San Juan UV Index data.

Average daily maximum UV levels by month for San Juan, Alajuela, Costa Rica.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 12 13 15 15 14 14 14 13 13 14 12 10