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San Juan, San Juan Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in San Juan, San Juan?
San Juan, San Juan gets 161 mm of precipitation a year over about 16 rainy days. January is the warmest month (average high 36°C) and July the coldest (average low -1°C).
Desert climate
San Juan, San Juan has hot summers and mild winters. Daytime highs range from about 18°C in July to 36°C in January. December is usually the wettest month. The most comfortable time to visit is typically May to September, when daytime highs sit near 21°C.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Jun–Aug | 1° | 19° |
| Spring | Sep–Nov | 11° | 29° |
| Summer | Dec–Feb | 19° | 36° |
| Autumn | Mar–May | 11° | 27° |
How much rain does San Juan get?
San Juan gets 161 mm of precipitation in an average year, spread over about 16 days with measurable rain. That is fewer rainy days than 99% of Argentina.
December is the wettest month, with 37 mm. July is the driest, with 2 mm. January has the most rainy days, about 3.
San Juan weather by month
San Juan weather in January
In January, San Juan averages a high of 36°C and a low of 20°C. It gets 26 mm of precipitation over about 3 rainy days. Estimated sunshine is 73% of daylight hours, derived from ERA5 cloud cover. The January record high is 46°C (2003) and the record low is 9°C (2019).
San Juan weather in February
In February, San Juan averages a high of 35°C and a low of 18°C. It gets 28 mm of precipitation over about 2 rainy days. Estimated sunshine is 71% of daylight hours, derived from ERA5 cloud cover. The February record high is 44°C (2025) and the record low is 6°C (2023).
San Juan weather in March
In March, San Juan averages a high of 32°C and a low of 16°C. It gets 24 mm of precipitation over about 2 rainy days. Estimated sunshine is 78% of daylight hours, derived from ERA5 cloud cover. The March record high is 42°C (2002) and the record low is 2°C (1977).
San Juan weather in April
In April, San Juan averages a high of 27°C and a low of 11°C. It gets 9 mm of precipitation over about 1 rainy days. Estimated sunshine is 79% of daylight hours, derived from ERA5 cloud cover. The April record high is 39°C (2002) and the record low is -3°C (1980).
San Juan weather in May
In May, San Juan averages a high of 22°C and a low of 6°C. It gets 3 mm of precipitation over about 1 rainy days. Estimated sunshine is 74% of daylight hours, derived from ERA5 cloud cover. The May record high is 35°C (2008) and the record low is -4°C (1993). May is one of the most comfortable months to visit.
San Juan weather in June
In June, San Juan averages a high of 18°C and a low of 1°C. It gets 5 mm of precipitation over about 1 rainy days. Estimated sunshine is 72% of daylight hours, derived from ERA5 cloud cover. The June record high is 32°C (2012) and the record low is -8°C (2011). June is one of the most comfortable months to visit.
San Juan weather in July
In July, San Juan averages a high of 18°C and a low of -1°C. It gets 2 mm of precipitation over about 1 rainy days. Estimated sunshine is 77% of daylight hours, derived from ERA5 cloud cover. The July record high is 33°C (2006) and the record low is -9°C (2011). July is one of the most comfortable months to visit.
San Juan weather in August
In August, San Juan averages a high of 21°C and a low of 2°C. It gets 6 mm of precipitation over about 1 rainy days. Estimated sunshine is 79% of daylight hours, derived from ERA5 cloud cover. The August record high is 38°C (2015) and the record low is -9°C (1981). August is one of the most comfortable months to visit.
San Juan weather in September
In September, San Juan averages a high of 25°C and a low of 7°C. It gets 8 mm of precipitation over about 1 rainy days. Estimated sunshine is 83% of daylight hours, derived from ERA5 cloud cover. The September record high is 39°C (2018) and the record low is -5°C (1974). September is one of the most comfortable months to visit.
San Juan weather in October
In October, San Juan averages a high of 29°C and a low of 11°C. It gets 3 mm of precipitation over about 1 rainy days. Estimated sunshine is 81% of daylight hours, derived from ERA5 cloud cover. The October record high is 42°C (2009) and the record low is 0°C (1979).
San Juan weather in November
In November, San Juan averages a high of 33°C and a low of 15°C. It gets 9 mm of precipitation over about 1 rainy days. Estimated sunshine is 79% of daylight hours, derived from ERA5 cloud cover. The November record high is 44°C (2009) and the record low is 1°C (1979).
San Juan weather in December
In December, San Juan averages a high of 36°C and a low of 18°C. It gets 37 mm of precipitation over about 2 rainy days. Estimated sunshine is 80% of daylight hours, derived from ERA5 cloud cover. The December record high is 46°C (2023) and the record low is 6°C (2014).
Sunshine, humidity and wind in San Juan
September is the sunniest month in San Juan, with estimated sunshine of 83% of daylight hours from ERA5 cloud cover. February is the cloudiest, at 71%. The annual cloud-cover estimate is 77% of daylight hours; it is not a measurement of sunshine duration. San Juan is sunnier than 99% of Argentina.
Humidity peaks in June at 54% and is lowest in September at 32%.
San Juan has about 51 days a year above 32°C. San Juan is hotter than 88% of Argentina.
First and last freeze in San Juan
The first fall freeze in San Juan typically comes around May 24, and the last spring freeze around September 5. That leaves a frost-free growing season of about 261 days.
San Juan weather records
These records cover SAN JUAN during 1973–2025. Earlier records or other stations in the city may differ.
The hottest temperature on record at the San Juan station is 46°C, on December 17, 2023. The coldest is -9°C, on August 30, 1981.
The wettest day in the available station history brought 200 mm of precipitation, on November 18, 1981.
31 all-time records have been set at the station since 1973.
The best time to visit San Juan
The most comfortable time to visit is typically May to September, when daytime highs sit near 21°C.
Winter (June–August) is mild, with average highs around 19°C and lows near 1°C.
Spring (September–November) is hot, with average highs around 29°C and lows near 11°C.
Summer (December–February) is hot, with average highs around 36°C and lows near 19°C.
Autumn (March–May) is warm, with average highs around 27°C and lows near 11°C.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | 20° | 36° | 26 mm | 3 | 40% | 73% | 46° | 9° |
| February | 18° | 35° | 28 mm | 2 | 43% | 71% | 44° | 6° |
| March | 16° | 32° | 24 mm | 2 | 47% | 78% | 42° | 2° |
| April | 11° | 27° | 9.4 mm | 1 | 51% | 79% | 39° | -3° |
| May | 6° | 22° | 3.3 mm | 1 | 52% | 74% | 35° | -4° |
| June | 1° | 18° | 5.3 mm | 1 | 54% | 72% | 32° | -8° |
| July | -1° | 18° | 1.5 mm | 1 | 48% | 77% | 33° | -9° |
| August | 2° | 21° | 6.1 mm | 1 | 38% | 79% | 38° | -9° |
| September | 7° | 25° | 7.9 mm | 1 | 32% | 83% | 39° | -5° |
| October | 11° | 29° | 2.5 mm | 1 | 35% | 81% | 42° | 0° |
| November | 15° | 33° | 9.4 mm | 1 | 35% | 79% | 44° | 1° |
| December | 18° | 36° | 37 mm | 2 | 36% | 80% | 46° | 6° |
Station: SAN JUAN, 11 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 1973–2025; record values refer to this station and period, not the entire city’s history. Precipitation includes rain and the water equivalent of frozen precipitation; snowfall depth is shown separately when available. Sources and methods
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
San Juan climate questions
How much rain does San Juan get?
San Juan gets 161 mm of precipitation in an average year, over about 16 rainy days.
What is the wettest month in San Juan?
December is the wettest month in San Juan, with 37 mm. July is the driest, with 2 mm.
How many rainy days does San Juan have a year?
San Juan has about 16 days with measurable rain in an average year. January has the most, about 3.
What is the hottest month in San Juan?
January is the warmest month in San Juan, with an average high of 36°C.
What is the coldest month in San Juan?
July is the coldest month in San Juan, with an average low of -1°C.
What is the record high temperature in San Juan?
Within the available 1973–2025 station history, the record high at the San Juan station is 46°C, set on December 17, 2023. The record low is -9°C, on August 30, 1981.
What is the sunniest month in San Juan?
September is the sunniest month in San Juan, with estimated sunshine of 83% of daylight hours from ERA5 cloud cover. February is the cloudiest.
When is the first frost in San Juan?
The first fall freeze in San Juan typically comes around May 24. The last spring freeze is around September 5.
What is the best time to visit San Juan?
The most comfortable time to visit is typically May to September, when daytime highs sit near 21°C.