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San Justo, Buenos Aires 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 Justo, Buenos Aires?
San Justo, Buenos Aires gets 1290 mm of precipitation a year over about 72 rainy days. January is the warmest month (average high 30°C) and July the coldest (average low 7°C).
Humid subtropical climate
San Justo, Buenos Aires has hot summers and mild winters. Daytime highs range from about 16°C in July to 30°C in January. December is usually the wettest month. The most comfortable time to visit is typically April to May and August to November, when daytime highs sit near 22°C.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Jun–Aug | 8° | 17° |
| Spring | Sep–Nov | 13° | 23° |
| Summer | Dec–Feb | 19° | 29° |
| Autumn | Mar–May | 14° | 23° |
How much rain does San Justo get?
San Justo gets 1290 mm of precipitation in an average year, spread over about 72 days with measurable rain. That is more rainy days than 87% of Argentina.
December is the wettest month, with 162 mm. June is the driest, with 31 mm. January has the most rainy days, about 8.
San Justo weather by month
San Justo weather in January
In January, San Justo averages a high of 30°C and a low of 20°C. It gets 150 mm of precipitation over about 8 rainy days. Estimated sunshine is 64% of daylight hours, derived from ERA5 cloud cover. The January record high is 42°C (2022) and the record low is 9°C (1988).
San Justo weather in February
In February, San Justo averages a high of 29°C and a low of 19°C. It gets 144 mm of precipitation over about 7 rainy days. Estimated sunshine is 61% of daylight hours, derived from ERA5 cloud cover. The February record high is 38°C (2025) and the record low is 8°C (2023).
San Justo weather in March
In March, San Justo averages a high of 27°C and a low of 18°C. It gets 94 mm of precipitation over about 6 rainy days. Estimated sunshine is 59% of daylight hours, derived from ERA5 cloud cover. The March record high is 39°C (2023) and the record low is 6°C (1990).
San Justo weather in April
In April, San Justo averages a high of 23°C and a low of 14°C. It gets 150 mm of precipitation over about 7 rainy days. Estimated sunshine is 60% of daylight hours, derived from ERA5 cloud cover. The April record high is 34°C (2004) and the record low is 3°C (1971). April is one of the most comfortable months to visit.
San Justo weather in May
In May, San Justo averages a high of 19°C and a low of 11°C. It gets 83 mm of precipitation over about 6 rainy days. Estimated sunshine is 54% of daylight hours, derived from ERA5 cloud cover. The May record high is 31°C (1972) and the record low is 0°C (1971). May is one of the most comfortable months to visit.
San Justo weather in June
In June, San Justo averages a high of 17°C and a low of 8°C. It gets 31 mm of precipitation over about 4 rainy days. Estimated sunshine is 45% of daylight hours, derived from ERA5 cloud cover. The June record high is 28°C (2024) and the record low is -2°C (1987).
San Justo weather in July
In July, San Justo averages a high of 16°C and a low of 7°C. It gets 60 mm of precipitation over about 5 rainy days. Estimated sunshine is 53% of daylight hours, derived from ERA5 cloud cover. The July record high is 30°C (1979) and the record low is -2°C (2025).
San Justo weather in August
In August, San Justo averages a high of 18°C and a low of 9°C. It gets 88 mm of precipitation over about 6 rainy days. Estimated sunshine is 54% of daylight hours, derived from ERA5 cloud cover. The August record high is 34°C (1996) and the record low is -2°C (1991). August is one of the most comfortable months to visit.
San Justo weather in September
In September, San Justo averages a high of 20°C and a low of 11°C. It gets 76 mm of precipitation over about 5 rainy days. Estimated sunshine is 52% of daylight hours, derived from ERA5 cloud cover. The September record high is 36°C (2013) and the record low is 1°C (1990). September is one of the most comfortable months to visit.
San Justo weather in October
In October, San Justo averages a high of 23°C and a low of 13°C. It gets 118 mm of precipitation over about 7 rainy days. Estimated sunshine is 59% of daylight hours, derived from ERA5 cloud cover. The October record high is 36°C (2021) and the record low is 1°C (1972). October is one of the most comfortable months to visit.
San Justo weather in November
In November, San Justo averages a high of 26°C and a low of 16°C. It gets 133 mm of precipitation over about 5 rainy days. Estimated sunshine is 62% of daylight hours, derived from ERA5 cloud cover. The November record high is 37°C (1985) and the record low is 4°C (1973). November is one of the most comfortable months to visit.
San Justo weather in December
In December, San Justo averages a high of 29°C and a low of 18°C. It gets 162 mm of precipitation over about 7 rainy days. Estimated sunshine is 64% of daylight hours, derived from ERA5 cloud cover. The December record high is 41°C (1995) and the record low is 6°C (1971).
Sunshine, humidity and wind in San Justo
January is the sunniest month in San Justo, with estimated sunshine of 64% of daylight hours from ERA5 cloud cover. June is the cloudiest, at 45%. The annual cloud-cover estimate is 57% of daylight hours; it is not a measurement of sunshine duration. San Justo is cloudier than 74% of Argentina.
Humidity peaks in June at 78% and is lowest in December at 62%.
San Justo has about 19 days a year above 32°C. San Justo is cooler than 59% of Argentina.
First and last freeze in San Justo
The first fall freeze in San Justo typically comes around June 30, and the last spring freeze around July 12. That leaves a frost-free growing season of about 353 days.
San Justo weather records
These records cover BUENOS AIRES OBSERV during 1970–2025. Earlier records or other stations in the city may differ.
The hottest temperature on record at the San Justo station is 42°C, on January 15, 2022. The coldest is -2°C, on August 1, 1991.
The wettest day in the available station history brought 300 mm of precipitation, on June 8, 1973.
30 all-time records have been set at the station since 1970.
The annual mean temperature has changed by +0.1°C per decade since 1970.
The best time to visit San Justo
The most comfortable time to visit is typically April to May and August to November, when daytime highs sit near 22°C.
Winter (June–August) is mild, with average highs around 17°C and lows near 8°C.
Spring (September–November) is warm, with average highs around 23°C and lows near 13°C.
Summer (December–February) is hot, with average highs around 29°C and lows near 19°C.
Autumn (March–May) is warm, with average highs around 23°C and lows near 14°C.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|
| January | 20° | 30° | 150 mm | 8 | 63% | 64% | 42° | 9° |
| February | 19° | 29° | 144 mm | 7 | 67% | 61% | 38° | 8° |
| March | 18° | 27° | 94 mm | 6 | 72% | 59% | 39° | 6° |
| April | 14° | 23° | 150 mm | 7 | 76% | 60% | 34° | 3° |
| May | 11° | 19° | 83 mm | 6 | 76% | 54% | 31° | 0° |
| June | 8° | 17° | 31 mm | 4 | 78% | 45% | 28° | -2° |
| July | 7° | 16° | 60 mm | 5 | 75% | 53% | 30° | -2° |
| August | 9° | 18° | 88 mm | 6 | 70% | 54% | 34° | -2° |
| September | 11° | 20° | 76 mm | 5 | 70% | 52% | 36° | 1° |
| October | 13° | 23° | 118 mm | 7 | 66% | 59% | 36° | 1° |
| November | 16° | 26° | 133 mm | 5 | 64% | 62% | 37° | 4° |
| December | 18° | 29° | 162 mm | 7 | 62% | 64% | 41° | 6° |
Station: BUENOS AIRES OBSERV, 13 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 1970–2025; 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 Justo climate questions
How much rain does San Justo get?
San Justo gets 1290 mm of precipitation in an average year, over about 72 rainy days.
What is the wettest month in San Justo?
December is the wettest month in San Justo, with 162 mm. June is the driest, with 31 mm.
How many rainy days does San Justo have a year?
San Justo has about 72 days with measurable rain in an average year. January has the most, about 8.
What is the hottest month in San Justo?
January is the warmest month in San Justo, with an average high of 30°C.
What is the coldest month in San Justo?
July is the coldest month in San Justo, with an average low of 7°C.
What is the record high temperature in San Justo?
Within the available 1970–2025 station history, the record high at the San Justo station is 42°C, set on January 15, 2022. The record low is -2°C, on August 1, 1991.
What is the sunniest month in San Justo?
January is the sunniest month in San Justo, with estimated sunshine of 64% of daylight hours from ERA5 cloud cover. June is the cloudiest.
When is the first frost in San Justo?
The first fall freeze in San Justo typically comes around June 30. The last spring freeze is around July 12.
What is the best time to visit San Justo?
The most comfortable time to visit is typically April to May and August to November, when daytime highs sit near 22°C.