December weather forecast
Bryn Mawr, CA

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Weather in December

December, the first month of the winter in Bryn Mawr, is still a refreshing month, with an average temperature varying between 41.4°F (5.2°C) and 58.8°F (14.9°C).

Temperature

December stands out as Bryn Mawr's coldest month, with temperatures ranging between an average high of 58.8°F (14.9°C) and a low of 41.4°F (5.2°C).

Humidity

In December, the average relative humidity is 51%.

Rainfall

December is the month with the most rainfall. Rain falls for 6.4 days and accumulates 1.42" (36mm) of precipitation.

Snowfall

In Bryn Mawr, snow does not fall in January, March through December.

Daylight

December has the shortest days of the year, with an average of 9h and 54min of daylight.
On the first day of December, sunrise is at 6:36 am and sunset at 4:39 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 4:50 pm PST.

Sunshine

December has the least sunshine of the year in Bryn Mawr, with an average of 6.8h of sunshine.

UV index

The month with the lowest UV index is December, with an average maximum UV index of 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for average individuals.
Note: A maximum high UV index of 3 in December translates into the following recommendations:
Be vigilant - Preventing sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.

Frequently asked questions

What time of the year is the coldest in Bryn Mawr?

December, marked by an average high-temperature of 58.8°F (14.9°C) and a low-temperature of 41.4°F (5.2°C), is the coldest month in Bryn Mawr.

What is the temperature in December in Bryn Mawr?

The average high-temperature and low-temperature in Bryn Mawr during December are 58.8°F (14.9°C) and 41.4°F (5.2°C) respectively. The average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines air temperature and relative humidity, in September is estimated at 86°F (30°C).

What is the average humidity in December in Bryn Mawr?

In Bryn Mawr, California, the average relative humidity in December is 51%.

What is the wettest month in Bryn Mawr?

The month with the most rainfall in Bryn Mawr, California, is December, when the rain falls for 6.4 days and typically aggregates up to 1.42" (36mm) of precipitation.

How much does it rain in Bryn Mawr in December?

In December, the rain falls for 6.4 days. Throughout December, 1.42" (36mm) of precipitation is accumulated.

When it does not snow in Bryn Mawr?

In Bryn Mawr, snow does not fall in January, March through December.

What is the month with the shortest days in Bryn Mawr?

With an average of 9h and 54min of daylight, December has the shortest days of the year.

What is the average length of the day in December in Bryn Mawr?

In December, the average day length in Bryn Mawr is 9h and 56min.

What time are sunrise and sunset in December in Bryn Mawr?

In December, on the first day of the month, sunrise is at 6:36 am and sunset at 4:39 pm. On the last day of the month, in Bryn Mawr, sunrise is at 6:54 am and sunset at 4:50 pm PST.

What is the month with the least sunshine in Bryn Mawr?

With an average of 6.8h of sunshine, December has the least sunshine of the year in Bryn Mawr.

How many hours of sunshine does Bryn Mawr have in December?

The average sunshine duration in December in Bryn Mawr is 6.8h.

What is the month with the lowest UV index in Bryn Mawr?

December is the month with the lowest UV index in Bryn Mawr, with an average maximum UV index of 3.

How high is the UV index in December in Bryn Mawr?

In December, the average daily maximum UV index in Bryn Mawr is 3. A UV Index reading of 3 to 5 represents a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Bryn Mawr, CA

Average temperature in December - Bryn Mawr, CA
  • Average high temperature in December: 58.8°F

The warmest months (with the highest average high temperature) are July and August (90.3°F).
The month with the lowest average high temperature is December (58.8°F).

  • Average low temperature in December: 41.4°F

The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is December (41.4°F).

Average pressure in December
Bryn Mawr, CA

Average pressure in December - Bryn Mawr, CA
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

Average wind speed in December
Bryn Mawr, CA

Average wind speed in December - Bryn Mawr, CA
  • Average wind speed in December: 5.4mph

The windiest month (with the highest average wind speed) is April (6.3mph).
The calmest month (with the lowest average wind speed) is September (4.7mph).

Average humidity in December
Bryn Mawr, CA

Average humidity in December - Bryn Mawr, CA
  • Average humidity in December: 51%

The month with the highest relative humidity is February (53%).
The month with the lowest relative humidity is August (37%).

Average rainfall in December
Bryn Mawr, CA

Average rainfall in December - Bryn Mawr, CA
  • Average rainfall in December: 1.42"

The wettest month (with the highest rainfall) is December (1.42").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in December
Bryn Mawr, CA

Average rainfall days in December - Bryn Mawr, CA
  • Average rainfall days in December: 6.4 days

The month with the highest number of rainy days is March (6.7 days).
The month with the least rainy days is June (1.3 days).

Average snowfall days in December
Bryn Mawr, CA

Average snowfall days in December - Bryn Mawr, CA
  • Average snowfall days in December: 0 days

The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

Average daylight in December /
Average sunshine in December
Bryn Mawr, CA

Average daylight in December / Average sunshine in December - Bryn Mawr, CA
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in December: 6h and 5min

The month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 6h and 48min).

Average sunshine days in December
Bryn Mawr, CA

Average sunshine days in December - Bryn Mawr, CA
  • Average sunshine days in December: 23.5 days

The month with the most sunshine days is June (28 days).
The month with the least sunshine days is February (21.3 days).

Average UV index in December
Bryn Mawr, CA

Average UV index in December - Bryn Mawr, CA
  • Average UV index in December: 3

The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in December
Bryn Mawr, CA

Average cloud cover in December - Bryn Mawr, CA
  • Average cloud cover in December: 22

The months with the most cloud cover are February, March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).

Average visibility in December
Bryn Mawr, CA

Average visibility in December - Bryn Mawr, 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).

Bryn Mawr, California, USA

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