Climate and monthly weather forecastSan Juan, Argentina
Climate and monthly weather forecast
The climate of San Juan
San Juan, located in Argentina, experiences a Mid-latitude desert climate categorized under the Köppen climate classification as BWk. Throughout the year, San Juan's weather is characterized by moderate temperatures, low humidity levels, sparse rainfall, and ample sunlight exposure.The temperature spectrum in San Juan ranges significantly, with a low of 4.5°C (40.1°F) recorded in July and a high of 30.6°C (87.1°F) noted in January. Generally, the yearly average temperature swings between these two extremes due to the desert climate. Regarding rainfall, the annual distribution is relatively uniform, with a record low of 1mm (0.04") per month during the winter months - June and July - and extends to a high of 29mm (1.14") in January. The number of rainfall days parallels the volume patterns, surging from a low of 1.3 days in August to a high of 9.2 days in January.
The humidity levels, as expected in a desert climate, are quite moderate, fluctuating from 35% in November to 52% in April and May. An intriguing aspect to note is that despite its desert classification, San Juan experiences minute amounts of snowfall concentrated primarily in June, July and August. Furthermore, while the city boasts an average visibility of 10km (6.2mi) throughout the year, the daylight hours stretch from 10.1h in June to a peak of 14.2h in December. The sunshine hours experience less variation, remaining fairly steady at 9.8h per day on average.
The best time to visit San Juan
The ideal time to visit San Juan would be in the spring months - September, October and November. During this time, the daytime temperatures vary from 20.5°C (68.9°F) to 27.6°C (81.7°F), making for a pleasant climate conducive to outdoor activities. Sunshine occurs for roughly 9.8h to 9.9h per day, coupled with moderate rainfall of 2mm (0.08") to 8mm (0.31"), assuring enjoyable weather for visitors. Furthermore, the sightseeing experience could be enhanced as the relative humidity levels are comparably lower - 38% in September to 35% in November.The worst time to visit San Juan
The winter period from June to August is considered less favorable for travels to San Juan. The temperatures during these months drop to their lowest of the year, ranging from 14.6°C (58.3°F) to 18.3°C (64.9°F) across the day, even plummeting to lows of 4.5°C (40.1°F) to 7.3°C (45.1°F) at night. Although the rainfall is minimal during this time, days are shorter and the city sees a drop in the average sunlight hours, 10.1h to 11h per day, which could influence outdoor activities and sightseeing.Spring weather in San Juan
During the spring, the weather in San Juan takes a pleasant turn. Day temperatures from September to November ascend from 20.5°C (68.9°F) to 27.6°C (81.7°F), while the nights host temperature drops to 9°C (48.2°F) and 14.9°C (58.8°F). Springtime also introduces a rise in average daylight hours, from 11h in September to 13.7h in November, alongside a steady sunshine duration of around 9.7h to 9.9h daily. This season sees minimal precipitation, and its relative humidity stands at an average of 37% across the three months, offering a comfortable atmosphere for outdoor exploration.Summer weather in San Juan
Summers in San Juan are characterized by hot conditions. Between December to February, the scorching daytime temperature soars to its peak, ranging from 29.8°C (85.6°F) to 30.6°C (87.1°F), cooling down slightly during night from 17.5°C (63.5°F) to 19.4°C (66.9°F). Despite the high temperatures, rainfall remains fairly low at 14mm (0.55") to 16mm (0.63"). These months experience the longest daylight hours of the year, extending from 13.7h in December to 13.9h in January. The direct sunlight duration is consistent, averaging 9.8h per day across the season.Autumn weather in San Juan
The autumnal months of March, April, and May in San Juan witness a gradual fall in temperatures. The daytime temperature in March starts at 26.7°C (80.1°F) and slowly drops to 19°C (66.2°F) in May, while the night temperatures cool down from 16°C (60.8°F) to 9.2°C (48.6°F). These months also encounter slightly increased rainfall, with April recording the highest rainfall of the season at 3mm (0.12"). Despite the temperatures gradually falling, the sunshine amount manages to stay approximately consistent at approximately 9.7h per day.Winter weather in San Juan
Winter in San Juan is cold and receives minimal precipitation. The low temperatures vary across June, July, and August, from 14.6°C (58.3°F) to 18.3°C (64.9°F), dipping further down at night to a chilly range of 4.5°C (40.1°F) to 7.3°C (45.1°F). Interestingly, despite its desert climate, San Juan experiences slight snowfall during these months, mainly in June and August, with 4mm (0.16") and 2mm (0.08") registered respectively. Yet, these months do boast an average of 9.8h of daily sunshine, indicating that the city's desert classification remains a steadfast part of its overall climate characteristics.Weather in January
January represents the height of summer in San Juan, Argentina, with conditions largely dominated by warm temperatures. High temperatures peak at an average of 30.6°C (87.1°F), with evenings cooling down to a more comfortable average of 19.4°C (66.9°F). Weather in January »Weather in February
February is the last of the summer months and maintains a high level of warmth throughout. The transition from January is barely noticeable, with only a slight decrease in maximum temperatures to 29.1°C (84.4°F). Argentinians celebrate the day of national sovereignty this month, often basking in the 13.2 hours of daylight. Weather in February »Weather in March
March marks the onset of autumn in San Juan with milder weather characteristics. Though temperatures start to dip, staying within a range of 19.4°C (66.9°F) to 26.7°C (80.1°F), many days remain warm. The UV index remains at 6, so adequate protection against the sun is crucial, even outside of the summer months. Weather in March »Weather in April
April continues to cool the city as thermal attire becomes indispensable. A notable decline in temperatures is observed, with highs settling near 22.9°C (73.2°F). This month is known for its excellent visibility, with clear skies throughout the day. Weather in April »Weather in May
Further deepening into autumn, May brings an appreciable reduction in temperatures. The weather favours the onset of winter as the highest daily temperatures only go up to an average of 19°C (66.2°F). Despite a reduction in the UV index to 3, daylight hours still remain sufficient for outdoor activities. Weather in May »Weather in June
June signals the arrival of winter in San Juan, Argentina. Chilly nights with average lows of 6.2°C (43.2°F) set a contrast to the milder daytime temperatures. Despite the decrease in temperature, the sun continues to shine, with daylight hours stretching up to 10.1 on average. Weather in June »Weather in July
July is the coolest month of the year in San Juan, with minimum temperatures dropping to an average of just 4.5°C (40.1°F). This period offers the chance to experience winter in Argentina in its full form. Although snowfall in San Juan is not a common occurrence, July sees trace amounts accumulating which can make for a picturesque setting. Weather in July »Weather in August
August brings a welcome relief from the intense cold of July, with the mercury rising slightly. The city begins to awaken from its winter sleep as temperatures start climbing up to 18.3°C (64.9°F). The daylight hours continue to increase, granting San Juan an additional 11 hours of sunlight on average. Weather in August »Weather in September
In September, spring arrives in San Juan, heralding a steady rise in temperatures. The weather is particularly pleasing, with the mercury reflecting a well-balanced range. The average wind speed in San Juan further rises to 11.1km/h (6.9mph), a clear sign that the transition from winter to spring is underway. Weather in September »Weather in October
October exhibits further warming, with an upswing in the city's climate. The people of San Juan continue to relish the spring weather as the temperatures start touching an average high of 23.8°C (74.8°F). The wind speed reaches a high as well, reaching average speeds of 12.2km/h (7.6mph) which helps keep the city feeling fresh and invigorating. Weather in October »Weather in November
As November unfolds, summer starts making its presence felt in San Juan again. The city sees the mercury slowly begin to climb, lending warmth to the air of Argentina. Interestingly, despite the trend of rising temperatures, November sees a slight decrease in daylight hours. Weather in November »Weather in December
December welcomes full-fledged summer to San Juan, Argentina. It is primarily characterised by a further rise in temperatures, where the days warm up to nearly 29.8°C (85.6°F) on average. However, this is balanced by cooler nights which offer some relief from the heat of the day. Weather in December »Updated: Jan 25, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
January is the month when San Juan sees the average highest temperatures, with a high of 30.6°C (87.1°F) and a low of 19.4°C (66.9°F).
The month with the most rainfall in San Juan is January, when the rain falls for 9.2 days and typically aggregates up to 29mm (1.14") of precipitation.
Throughout the year, in San Juan, Argentina, there are 50.2 rainfall days, and 94mm (3.7") of precipitation is accumulated.
January through June, October through December are months without snowfall.
Throughout the year, in San Juan, Argentina, 8mm (0.31") of snow is accumulated.
With an average maximum UV index of 7, January is the month with the highest UV index in San Juan, Argentina.
March through May and October, with an average of 9.7h of sunshine, are months with the least sunshine.
The months with the highest humidity in San Juan are April and May, with an average relative humidity of 52%.
The months with the lowest UV index in San Juan, Argentina, are May through July, with an average maximum UV index of 3.
June and July are months with the least rain in San Juan, Argentina, when the rain falls for 1.8 days and typically aggregates up to 1mm (0.04") of rain.
The month with the shortest days is June, with an average of 10h and 6min of daylight.
July is the month that records the lowest temperatures in San Juan, Argentina, with averages ranging from a high of 14.6°C (58.3°F) to a low of 4.5°C (40.1°F).
Months with snowfall are July through September.
The month with the most snowfall is July, when snow falls for 0.4 days and typically aggregates up to 4mm (0.16") of snow.
August, September and November, with an average of 9.9h of sunshine, are months with the most sunshine in San Juan.
The least humid month in San Juan, Argentina, is November, with an average relative humidity of 35%.
With an average of 14h and 12min of daylight, December has the longest days of the year in San Juan, Argentina.
San Juan, Argentina, does not utilize Daylight Saving Time (DST). -03 timezone is used over the entire year.
Average temperature
San Juan, Argentina
The warmest month (with the highest average high temperature) is January (30.6°C).
The month with the lowest average high temperature is July (14.6°C).
The month with the highest average low temperature is January (19.4°C).
The coldest month (with the lowest average low temperature) is July (4.5°C).
Average pressure
San Juan, Argentina
- Average pressure in January:
1011.1mbar - Average pressure in February:
1011.6mbar - Average pressure in March:
1013.4mbar - Average pressure in April:
1015.4mbar - Average pressure in May:
1016.4mbar - Average pressure in June:
1017.1mbar
- Average pressure in July:
1018.1mbar - Average pressure in August:
1017mbar - Average pressure in September:
1016.3mbar - Average pressure in October:
1013.7mbar - Average pressure in November:
1011.7mbar - Average pressure in December:
1010.2mbar
The month with the highest atmospheric pressure is July (1018.1mbar).
The month with the lowest atmospheric pressure is December (1010.2mbar).
Average wind speed
San Juan, Argentina
- Average wind speed in January:
10.6km/h - Average wind speed in February:
10.5km/h - Average wind speed in March:
9.9km/h - Average wind speed in April:
9.4km/h - Average wind speed in May:
8.8km/h - Average wind speed in June:
9km/h
- Average wind speed in July:
9.2km/h - Average wind speed in August:
10.2km/h - Average wind speed in September:
11.1km/h - Average wind speed in October:
12.2km/h - Average wind speed in November:
12.2km/h - Average wind speed in December:
11.7km/h
The windiest months (with the highest average wind speed) are October and November (12.2km/h).
The calmest month (with the lowest average wind speed) is May (8.8km/h).
Average humidity
San Juan, Argentina
The months with the highest relative humidity are April and May (52%).
The month with the lowest relative humidity is November (35%).
Average rainfall
San Juan, Argentina
The wettest month (with the highest rainfall) is January (29mm).
The driest months (with the least rainfall) are June and July (1mm).
Average rainfall days
San Juan, Argentina
- Average rainfall days in January:
9.2 days - Average rainfall days in February:
7 days - Average rainfall days in March:
6 days - Average rainfall days in April:
3.8 days - Average rainfall days in May:
2.3 days - Average rainfall days in June:
1.8 days
- Average rainfall days in July:
1.6 days - Average rainfall days in August:
1.3 days - Average rainfall days in September:
1.9 days - Average rainfall days in October:
3 days - Average rainfall days in November:
4.2 days - Average rainfall days in December:
8.1 days
The month with the highest number of rainy days is January (9.2 days).
The month with the least rainy days is August (1.3 days).
Average snowfall
San Juan, Argentina
The month with the highest snowfall is July (4mm).
The months with the least snowfall are January, February, March, April, May, June, October, November and December (0mm).
Average snowfall days
San Juan, Argentina
- Average snowfall days in January:
0 days - Average snowfall days in February:
0 days - Average snowfall days in March:
0 days - Average snowfall days in April:
0 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0.4 days - Average snowfall days in August:
0.3 days - Average snowfall days in September:
0.4 days - Average snowfall days in October:
0 days - Average snowfall days in November:
0 days - Average snowfall days in December:
0 days
The months with the highest number of snowfall days are July and September (0.4 days).
The months with the least snowfall days are January, February, March, April, May, June, October, November and December (0 days).
Average daylight / Average sunshine
San Juan, Argentina
- Average daylight in January:
13h and 54min - Average daylight in February:
13h and 12min - Average daylight in March:
12h and 18min - Average daylight in April:
11h and 18min - Average daylight in May:
10h and 30min - Average daylight in June:
10h and 6min
- Average daylight in July:
10h and 18min - Average daylight in August:
11h and 0min - Average daylight in September:
11h and 54min - Average daylight in October:
12h and 54min - Average daylight in November:
13h and 42min - Average daylight in December:
14h and 12min
The month with the longest days is December (Average daylight: 14h and 12min).
The month with the shortest days is June (Average daylight: 10h and 6min).
- Average sunshine in January:
9h and 48min - Average sunshine in February:
9h and 48min - Average sunshine in March:
9h and 42min - Average sunshine in April:
9h and 42min - Average sunshine in May:
9h and 42min - Average sunshine in June:
9h and 48min
- Average sunshine in July:
9h and 48min - Average sunshine in August:
9h and 54min - Average sunshine in September:
9h and 54min - Average sunshine in October:
9h and 42min - Average sunshine in November:
9h and 54min - Average sunshine in December:
9h and 48min
The months with the most sunshine are August, September and November (Average sunshine: 9h and 54min).
The months with the least sunshine are March, April, May and October (Average sunshine: 9h and 42min).
Average sunshine days
San Juan, Argentina
- Average sunshine days in January:
15.4 days - Average sunshine days in February:
16.8 days - Average sunshine days in March:
22.2 days - Average sunshine days in April:
24 days - Average sunshine days in May:
28.2 days - Average sunshine days in June:
27.9 days
- Average sunshine days in July:
29.7 days - Average sunshine days in August:
29.3 days - Average sunshine days in September:
26.9 days - Average sunshine days in October:
25.2 days - Average sunshine days in November:
21.8 days - Average sunshine days in December:
18.5 days
The month with the most sunshine days is July (29.7 days).
The month with the least sunshine days is January (15.4 days).
Average UV index
San Juan, Argentina
The month with the highest UV index is January (UV index 7).
The months with the lowest UV index are May, June and July (UV index 3).
Average cloud cover
San Juan, Argentina
The months with the most cloud cover are March, April and May (Cloud cover 12).
The month with the least cloud cover is August (Cloud cover 8).
Average visibility
San Juan, Argentina
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
