December weather forecastSan Luis Obispo, CA

Beautiful blue water surrounded by scenic mountain ranges at the San Luis Obispo, CaliforniaBeautiful blue water surrounded by scenic mountain ranges at the San Luis Obispo, California

December

Weather in December

The first month of the winter, December, is still a refreshing month in San Luis Obispo, California, with an average temperature fluctuating between 60.3°F (15.7°C) and 46.2°F (7.9°C).

Temperature

The lowest temperatures are recorded in December, with averages reaching a high of 60.3°F (15.7°C) and a low of 46.2°F (7.9°C).

Humidity

The average relative humidity in December in San Luis Obispo, California, is 64%.

Rainfall

In San Luis Obispo, during December, the rain falls for 7.7 days and regularly aggregates up to 1.46" (37mm) of precipitation. In San Luis Obispo, during the entire year, the rain falls for 57 days and collects up to 9.57" (243mm) of precipitation.

Daylight

With an average of 9h and 48min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 6:53 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 5:00 pm PST.

Sunshine

February and December, with an average of 6.5h of sunshine, are months with the least sunshine.

UV index

In San Luis Obispo, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for average individuals.
Note: The maximum daily UV index of 4 during December translates into the following directions:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Updated: Jul 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

With average high and low temperatures of 60.3°F (15.7°C) and 46.2°F (7.9°C) respectively, December is San Luis Obispo's coldest month.

San Luis Obispo in December has an average high-temperature of 60.3°F (15.7°C) and an average low-temperature of 46.2°F (7.9°C).

In December, the average relative humidity is 64%.

In San Luis Obispo, during December, the rain falls for 7.7 days and regularly aggregates up to 1.46" (37mm) of precipitation.

With an average of 9h and 48min of daylight, December has the shortest days of the year.

In December, the average day length is 9h and 49min.

In December, on the first day of the month, sunrise is at 6:53 am and sunset at 4:50 pm. On the last day of the month, in San Luis Obispo, sunrise is at 7:11 am and sunset at 5:00 pm PST.

February and December, with an average of 6.5h of sunshine, are months with the least sunshine.

The average sunshine duration in December in San Luis Obispo is 6.5h.

In December, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to the Sun's UV radiation.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
San Luis Obispo, CA

  • Average high temperature in December: 60.3°F

The warmest month (with the highest average high temperature) is August (80.2°F).
The month with the lowest average high temperature is December (60.3°F).

  • Average low temperature in December: 46.2°F

The month with the highest average low temperature is September (60.3°F).
The coldest month (with the lowest average low temperature) is February (45.7°F).

Average pressure in December
San Luis Obispo, CA

  • Average pressure in December: 30.09"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).

Average wind speed in December
San Luis Obispo, CA

  • Average wind speed in December: 6.2mph

The windiest months (with the highest average wind speed) are April and May (6.8mph).
The calmest months (with the lowest average wind speed) are August and September (5.3mph).

Average humidity in December
San Luis Obispo, CA

  • Average humidity in December: 64%

The month with the highest relative humidity is March (69%).
The months with the lowest relative humidity are September and October (57%).

Average rainfall in December
San Luis Obispo, CA

  • Average rainfall in December: 1.46"

The wettest month (with the highest rainfall) is March (2.01").
The driest months (with the least rainfall) are June and August (0.04").

Average rainfall days in December
San Luis Obispo, CA

  • Average rainfall days in December: 7.7 days

The month with the highest number of rainy days is March (10.5 days).
The month with the least rainy days is August (0.6 days).

Average daylight in December /
Average sunshine in December
San Luis Obispo, CA

  • Average daylight in December: 9h and 48min

The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 48min).

  • Average sunshine in December: 6h and 30min

The months with the most sunshine are June, July and August (Average sunshine: 12h and 0min).
The months with the least sunshine are February and December (Average sunshine: 6h and 30min).

Average sunshine days in December
San Luis Obispo, CA

  • Average sunshine days in December: 22.2 days

The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is February (19.1 days).

Average UV index in December
San Luis Obispo, CA

  • Average UV index in December: 4

The months with the highest UV index are June and August (UV index 6).
The month with the lowest UV index is February (UV index 3).

Average cloud cover in December
San Luis Obispo, CA

  • Average cloud cover in December: 25

The month with the most cloud cover is March (Cloud cover 28).
The months with the least cloud cover are August and September (Cloud cover 6).

Average visibility in December
San Luis Obispo, CA

  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).