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Monthly climate in San Isidro, Costa Rica

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification San Isidro features a tropical rainforest climate (Af). Temperatures typically range between 22 °C (72 °F) and 23 °C (73 °F) through the year, but rarely can drop to 17 °C (64 °F) or can rise to as high as 27 °C (80 °F). The average annual precipitation amounts to about 6731 mm (265.0 inches) and receives 342 rainy days on the 1 mm (0.04 inches) threshold annually. San Isidro enjoys an average of 3144 hours of sunshine throughout the year, and daylight varies from 11 hours 34 minutes to 12 hours 38 minutes per day.

Monthly average temperatures in San Isidro, Costa Rica

The warmest months in San Isidro are April, May and June, with daily mean temperatures ranging from 23 to 23 °C (73 - 73 °F) throughout the day. The coldest temperatures usually occur in January, November and December, when daily mean temperatures range from 22 to 22 °C (72 - 72 °F) throughout the day. On average each year, San Isidro experiences 31 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 Isidro. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum25°C
(78°F)		26°C
(79°F)		26°C
(79°F)		26°C
(79°F)		27°C
(80°F)		26°C
(79°F)		25°C
(78°F)		26°C
(78°F)		26°C
(78°F)		25°C
(78°F)		25°C
(77°F)		25°C
(77°F)
Mean maximum25°C
(77°F)		25°C
(77°F)		25°C
(78°F)		25°C
(78°F)		26°C
(79°F)		26°C
(79°F)		25°C
(77°F)		25°C
(78°F)		25°C
(78°F)		25°C
(77°F)		24°C
(76°F)		25°C
(76°F)
Average high24°C
(75°F)		24°C
(76°F)		24°C
(76°F)		24°C
(76°F)		24°C
(76°F)		24°C
(76°F)		24°C
(76°F)		24°C
(76°F)		24°C
(76°F)		24°C
(75°F)		24°C
(75°F)		24°C
(75°F)
Daily mean22°C
(72°F)		22°C
(73°F)		23°C
(73°F)		23°C
(73°F)		23°C
(73°F)		23°C
(73°F)		22°C
(73°F)		22°C
(73°F)		22°C
(72°F)		22°C
(72°F)		22°C
(72°F)		22°C
(72°F)
Average low20°C
(68°F)		20°C
(69°F)		21°C
(69°F)		21°C
(70°F)		21°C
(71°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
(68°F)
Mean minimum19°C
(66°F)		19°C
(66°F)		19°C
(67°F)		20°C
(68°F)		21°C
(69°F)		20°C
(69°F)		20°C
(69°F)		20°C
(68°F)		20°C
(68°F)		20°C
(67°F)		19°C
(67°F)		19°C
(66°F)
Minimum18°C
(65°F)		17°C
(64°F)		19°C
(66°F)		19°C
(67°F)		20°C
(68°F)		20°C
(68°F)		20°C
(67°F)		19°C
(67°F)		20°C
(68°F)		19°C
(67°F)		19°C
(67°F)		18°C
(65°F)

Compare climate in San Isidro with other places

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

Monthly average precipitation in San Isidro, Costa Rica

San Isidro usually has the most precipitation in August, October and November, with an average of 30 rainy days and 886 mm (34.9 inches) of precipitation per month. The driest months in San Isidro are January, February and March. On average, 138 mm (5.4 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in San Isidro. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)194 (7.6)99 (3.9)120 (4.7)350 (13.8)742 (29.2)663 (26.1)784 (30.8)838 (33.0)766 (30.1)937 (36.9)885 (34.8)354 (13.9)
Average precipitation days (≥ 1 mm)212326303130313130303029

Monthly sunshine hours in San Isidro, Costa Rica

The sunniest months in San Isidro are February, March and December, when the sun shines an average of 10 hours 18 minutes a day. Least sunny months in San Isidro: May, September and October receive an average of 7 hours 24 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in San Isidro. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours253298333293230241249240231220247305
Mean daily daylight hours11h 37m11h 49m12h 3m12h 19m12h 32m12h 38m12h 35m12h 23m12h 9m11h 53m11h 40m11h 34m

Solar UV radiation in San Isidro, Costa Rica

San Isidro experiences the highest level of ultraviolet (UV) radiation in March, April and May, when the maximum UV index can reach values of 15 - 15, which corresponds to the Extreme category of sun exposure. January, November and December are in the 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 Isidro UV Index data.

Average daily maximum UV levels by month for San Isidro. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)121415151514141414141211