December weather forecast
San Juan, Argentina

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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. Wind speeds show a slight reduction from November's figures, averaging around 11.7km/h (7.3mph). Nevertheless, the onset of summer does not deter rainfall activity, recording a significant increase to 16mm (0.63"), spread over 8.1 days. This results in a pleasant mix of sunny and rainy days throughout the festive season.

Temperature

With the arrival of December, San Juan's average high-temperature registers at a still warm 29.8°C (85.6°F), indicating a subtle variation from the previous month. San Juan reports a significant contrast between daytime and nighttime temperatures, with an average low of 17.5°C (63.5°F) in December.

Humidity

In December, the average relative humidity in San Juan is 37%.

Rainfall

In San Juan, Argentina, during December, the rain falls for 8.1 days and regularly aggregates up to 16mm (0.63") of precipitation. Throughout the year, there are 50.2 rainfall days, and 94mm (3.7") of precipitation is accumulated.

Snowfall

January through June, October through December are months without snowfall.

Daylight

December has the longest days of the year, with an average of 14h and 12min of daylight.
On the first day of December in San Juan, sunrise is at 06:21 and sunset at 20:25. On the last day of the month, sunrise is at 06:32 and sunset at 20:42 -03.

Sunshine

In December, the average sunshine in San Juan is 9.8h.

UV index

In December, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for average individuals.
Note: A maximum high daily UV index of 6 during December translates into the following directions:
Endorse precautions and be consistent with sun safety guidelines. Preventing sunburn is paramount. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. Experience reduced UV exposure by about half when donning a wide-brim hat.

Frequently asked questions

How hot does it get in San Juan in December?

In December, in San Juan, the average high-temperature is 29.8°C (85.6°F), and the average low-temperature is 17.5°C (63.5°F). In February, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines air temperature and relative humidity, is calculated to be 29°C (84.2°F).

What is the average humidity in December in San Juan?

In San Juan, the average relative humidity in December is 37%.

How much does it rain in San Juan in December?

In San Juan, Argentina, in December, during 8.1 rainfall days, 16mm (0.63") of precipitation is typically accumulated.

When it does not snow in San Juan?

In San Juan, snow does not fall in January through June, October through December.

When are the longest days in San Juan?

With an average of 14h and 12min of daylight, December has the longest days of the year in San Juan, Argentina.

How many hours of daylight does San Juan have in December?

In San Juan, Argentina, the average day length in December is 14h and 10min.

When are sunrise and sunset in December in San Juan?

On the first day of December in San Juan, sunrise is at 06:21 and sunset at 20:25. On the last day of the month, sunrise is at 06:32 and sunset at 20:42 -03.

How long on average sun shines in December in San Juan?

In San Juan, Argentina, the average sunshine duration in December is 9.8h.

What is the UV index intensity in December in San Juan?

In San Juan, Argentina, the average daily maximum UV index in December is 6. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover

Average temperature in December
San Juan, Argentina

Average temperature in December - San Juan, Argentina
  • Average high temperature in December: 29.8°C

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).

  • Average low temperature in December: 17.5°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 in December
San Juan, Argentina

Average pressure in December - San Juan, Argentina
  • 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 in December
San Juan, Argentina

Average wind speed in December - San Juan, Argentina
  • 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 in December
San Juan, Argentina

Average humidity in December - San Juan, Argentina
  • Average humidity in December: 37%

The months with the highest relative humidity are April and May (52%).
The month with the lowest relative humidity is November (35%).

Average rainfall in December
San Juan, Argentina

Average rainfall in December - San Juan, Argentina
  • Average rainfall in December: 16mm

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 in December
San Juan, Argentina

Average rainfall days in December - San Juan, Argentina
  • 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 in December
San Juan, Argentina

Average snowfall in December - San Juan, Argentina
  • Average snowfall in December: 0mm

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 in December
San Juan, Argentina

Average snowfall days in December - San Juan, Argentina
  • 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 in December /
Average sunshine in December
San Juan, Argentina

Average daylight in December / Average sunshine in December - San Juan, Argentina
  • Average daylight in December: 14h and 1min

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 December: 9h and 5min

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 in December
San Juan, Argentina

Average sunshine days in December - San Juan, Argentina
  • 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 in December
San Juan, Argentina

Average UV index in December - San Juan, Argentina
  • Average UV index in December: 6

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 in December
San Juan, Argentina

Average cloud cover in December - San Juan, Argentina
  • Average cloud cover in December: 9

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 in December
San Juan, Argentina

Average visibility in December - San Juan, Argentina
  • Average visibility in December: 10km

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).

San Juan, Argentina

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