December weather forecastJohnstown, PA
December
Weather in December
Although less extreme than its consecutive months, December in Johnstown, Pennsylvania does not fall short in terms of its wintry essence. The cold wind, low temperatures, and short days define a typical winter environment. A minor detail not to overlook is the increased percentage of humidity towards the end of the year. This month witnesses temperatures declining to a low point of 26.1°F (-3.3°C), a sign that the harsh winter is just around the corner. As the days shorten, the festive season prepares the city for the upcoming colder months.Temperature
December brings a decrease in the average high-temperature, falling from November's frosty 46.6°F (8.1°C) to a wintry 36.9°F (2.7°C). Johnstown experiences a consistent average temperature of 26.1°F (-3.3°C) throughout the nights in December.Humidity
The average relative humidity in December is 85%.Rainfall
In Johnstown, in December, it is raining for 9.4 days, with typically 1.85" (47mm) of accumulated precipitation. Throughout the year, there are 152.7 rainfall days, and 21.1" (536mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, October through December. In Johnstown, in December, during 8.1 snowfall days, 2.8" (71mm) of snow is typically accumulated. In Johnstown, during the entire year, snow falls for 47.7 days and aggregates up to 18.23" (463mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of December, sunrise is at 7:19 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:38 am and sunset at 4:59 pm EST.
Sunshine
In Johnstown, the average sunshine in December is 3.4h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: A typical high UV index of 1 in December suggests the following recommendations:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Johnstown, PA
- Average high temperature in December: 36.9°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (30.7°F).
- Average low temperature in December: 26.1°F
The month with the highest average low temperature is July (58.8°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
Johnstown, PA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in December
Johnstown, PA
- Average wind speed in December: 9.4mph
The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in December
Johnstown, PA
- Average humidity in December: 85%
The month with the highest relative humidity is February (87%).
The month with the lowest relative humidity is July (78%).
Average rainfall in December
Johnstown, PA
- Average rainfall in December: 1.85"
The wettest month (with the highest rainfall) is May (2.56").
The driest month (with the least rainfall) is November (1.1").
Average rainfall days in December
Johnstown, PA
- Average rainfall days in December: 9.4 days
The month with the highest number of rainy days is May (19.8 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in December
Johnstown, PA
- Average snowfall in December: 2.8"
The month with the highest snowfall is March (4.21").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Johnstown, PA
- Average snowfall days in December: 8.1 days
The month with the highest number of snowfall days is January (12 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Johnstown, PA
- Average daylight in December: 9h and 24min
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: 3h and 24min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).
Average sunshine days in December
Johnstown, PA
- Average sunshine days in December: 15.4 days
The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is May (9 days).
Average UV index in December
Johnstown, PA
- Average UV index in December: 1
The months with the highest UV index are May, June, July and August (UV index 5).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Johnstown, PA
- Average cloud cover in December: 67
The month with the most cloud cover is January (Cloud cover 72).
The month with the least cloud cover is August (Cloud cover 39).
Average visibility in December
Johnstown, PA
- Average visibility in December: 5mi
The month with the highest visibility is April (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October, November and December (5mi).
