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Monthly climate in San Juan, Argentina

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification San Juan features a cold desert climate (BWk). Temperatures typically range between 9 °C (48 °F) and 27 °C (80 °F) through the year, but rarely can drop to -5 °C (24 °F) or can rise to as high as 42 °C (108 °F). The average annual precipitation amounts to about 154 mm (6.0 inches) and receives 29 rainy days on the 1 mm (0.04 inches) threshold annually. San Juan enjoys an average of 3860 hours of sunshine throughout the year, and daylight varies from 10 hours 6 minutes to 14 hours 8 minutes per day.

Monthly average temperatures in San Juan, Argentina

The warmest months in San Juan are January, February and December, with daily mean temperatures ranging from 25 to 27 °C (77 - 80 °F) throughout the day. The coldest temperatures usually occur in June, July and August, when daily mean temperatures range from 9 to 12 °C (48 - 54 °F) throughout the day. On average each year, San Juan experiences 186 days above 25 °C (77.0 °F) and 12 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. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum41°C
(106°F)		40°C
(105°F)		39°C
(103°F)		35°C
(96°F)		29°C
(85°F)		28°C
(82°F)		26°C
(78°F)		34°C
(94°F)		37°C
(100°F)		38°C
(100°F)		38°C
(100°F)		42°C
(108°F)
Mean maximum40°C
(104°F)		38°C
(101°F)		37°C
(98°F)		33°C
(92°F)		27°C
(82°F)		24°C
(75°F)		25°C
(78°F)		31°C
(88°F)		35°C
(95°F)		36°C
(98°F)		36°C
(98°F)		40°C
(105°F)
Average high33°C
(92°F)		31°C
(89°F)		29°C
(85°F)		26°C
(79°F)		21°C
(70°F)		18°C
(64°F)		17°C
(63°F)		21°C
(70°F)		24°C
(75°F)		27°C
(81°F)		30°C
(86°F)		32°C
(89°F)
Daily mean27°C
(80°F)		25°C
(77°F)		22°C
(72°F)		18°C
(65°F)		14°C
(57°F)		9°C
(49°F)		9°C
(48°F)		12°C
(54°F)		16°C
(61°F)		19°C
(67°F)		23°C
(73°F)		25°C
(77°F)
Average low20°C
(68°F)		18°C
(65°F)		15°C
(60°F)		12°C
(53°F)		7°C
(45°F)		3°C
(37°F)		2°C
(36°F)		4°C
(40°F)		9°C
(48°F)		12°C
(54°F)		15°C
(60°F)		18°C
(64°F)
Mean minimum13°C
(56°F)		13°C
(55°F)		9°C
(48°F)		6°C
(43°F)		1°C
(33°F)		-2°C
(29°F)		-3°C
(26°F)		-1°C
(30°F)		1°C
(35°F)		4°C
(39°F)		9°C
(49°F)		12°C
(53°F)
Minimum10°C
(51°F)		12°C
(53°F)		6°C
(43°F)		4°C
(39°F)		-2°C
(29°F)		-4°C
(25°F)		-5°C
(24°F)		-4°C
(25°F)		0°C
(32°F)		2°C
(36°F)		6°C
(44°F)		10°C
(50°F)

Compare climate in San Juan with other places

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

Monthly average precipitation in San Juan, Argentina

San Juan usually has the most precipitation in January, February and December, with an average of 2 rainy days and 18 mm (0.7 inches) of precipitation per month. The driest months in San Juan are June, July and August. On average, 6 mm (0.2 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in San Juan. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)19 (0.8)17 (0.7)17 (0.7)15 (0.6)11 (0.4)6 (0.2)8 (0.3)3 (0.1)12 (0.5)13 (0.5)14 (0.5)18 (0.7)
Average precipitation days (≥ 1 mm)233342202323

Monthly sunshine hours in San Juan, Argentina

The sunniest months in San Juan are October, November and December, when the sun shines an average of 12 hours 7 minutes a day. Least sunny months in San Juan: May, June and July receive an average of 9 hours 9 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in San Juan. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours310322337289277275289316325353371390
Mean daily daylight hours13h 54m13h 10m12h 13m11h 16m10h 29m10h 6m10h 19m11h 0m11h 54m12h 52m13h 42m14h 8m

Solar UV radiation in San Juan, Argentina

San Juan experiences the highest level of ultraviolet (UV) radiation in January, November and December, when the maximum UV index can reach values of 14 - 15, which corresponds to the Extreme category of sun exposure. May, June and July are in the Moderate / High exposure category. In these months, the maximum values of the UV index do not exceed 6. For more detailed information, check out our hourly San Juan UV Index data.

Average daily maximum UV levels by month for San Juan. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)151412964579121415