Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
December
Weather in December
Temperature
December signifies a minor drop in average high-temperature, transitioning from a fresh 52.7°F (11.5°C) in November to a frosty 44.1°F (6.7°C). Swarthmore experiences a steady low-temperature of 32.9°F (0.5°C) throughout December.Humidity
The months with the highest humidity are February, October and December, with an average relative humidity of 77%.Rainfall
In Swarthmore, during December, the rain falls for 8.7 days and regularly aggregates up to 2.32" (59mm) of precipitation. Throughout the year, there are 148.4 rainfall days, and 25.94" (659mm) of precipitation is accumulated.Snowfall
January through May, November and December are months with snowfall. In December, it is snowing for 1.5 days. Throughout December, 0.91" (23mm) of snow is accumulated. In Swarthmore, during the entire year, snow falls for 12.6 days and aggregates up to 7.28" (185mm) of snow.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:04 am and sunset at 4:36 pm. On the last day of December, sunrise is at 7:22 am and sunset at 4:46 pm EST.
Sunshine
The average sunshine in December is 5.1h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 2 in December interprets into the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is December cold?
What is the most humid month?
What is the average humidity in December?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Swarthmore have in December?
When are sunrise and sunset in December?
How long on average sun shines in December?
What are the months with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Swarthmore, PA
- Average high temperature in December: 44.1°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.4°F).
- Average low temperature in December: 32.9°F
The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).
Average pressure in December
Swarthmore, PA
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in December
Swarthmore, PA
- Average wind speed in December: 7.9mph
The windiest month (with the highest average wind speed) is March (8.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).
Average humidity in December
Swarthmore, PA
- Average humidity in December: 77%
The months with the highest relative humidity are February, October and December (77%).
The month with the lowest relative humidity is April (71%).
Average rainfall in December
Swarthmore, PA
- Average rainfall in December: 2.32"
The wettest month (with the highest rainfall) is August (3.11").
The driest month (with the least rainfall) is January (1.61").
Average rainfall days in December
Swarthmore, PA
- Average rainfall days in December: 8.7 days
The month with the highest number of rainy days is July (17 days).
The month with the least rainy days is January (7.1 days).
Average snowfall in December
Swarthmore, PA
- Average snowfall in December: 0.91"
The month with the highest snowfall is March (2.32").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Swarthmore, PA
- Average snowfall days in December: 1.5 days
The month with the highest number of snowfall days is February (3.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Swarthmore, PA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 5h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).
Average sunshine days in December
Swarthmore, PA
- Average sunshine days in December: 20.5 days
The month with the most sunshine days is January (20.8 days).
The month with the least sunshine days is July (11.3 days).
Average UV index in December
Swarthmore, PA
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Swarthmore, PA
- Average cloud cover in December: 45
The month with the most cloud cover is February (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in December
Swarthmore, PA
- 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).