Hourly Weather Forecast - Mercersburg, PA

12 AM
26°F
0%
6mph
NW
Clear
Humidity
52%
Feels like
19°F
Dew Point
11°F
1 AM
26°F
0%
6mph
NW
Clear
Humidity
53%
Feels like
19°F
Dew Point
11°F
2 AM
25°F
0%
5mph
NW
Clear
Humidity
54%
Feels like
19°F
Dew Point
11°F
3 AM
25°F
0%
4mph
NW
Clear
Humidity
55%
Feels like
19°F
Dew Point
11°F
4 AM
24°F
0%
4mph
NW
Clear
Humidity
56%
Feels like
19°F
Dew Point
11°F
5 AM
24°F
0%
4mph
NW
Mostly Clear
Humidity
58%
Feels like
19°F
Dew Point
11°F
6 AM
23°F
0%
3mph
NW
Partly Cloudy
Humidity
60%
Feels like
19°F
Dew Point
12°F
7 AM
24°F
0%
3mph
NW
Cloudy
Humidity
61%
Feels like
20°F
Dew Point
13°F
7:29 AM
8 AM
25°F
0%
3mph
NW
Cloudy
Humidity
60%
Feels like
25°F
Dew Point
13°F
9 AM
28°F
0%
3mph
NW
Cloudy
Humidity
56%
Feels like
28°F
Dew Point
14°F
10 AM
30°F
0%
3mph
NW
Cloudy
Humidity
53%
Feels like
30°F
Dew Point
15°F
11 AM
32°F
0%
2mph
NW
Cloudy
Humidity
49%
Feels like
32°F
Dew Point
15°F
12 PM
34°F
0%
2mph
WNW
Cloudy
Humidity
46%
Feels like
34°F
Dew Point
15°F
1 PM
36°F
0%
2mph
WNW
Cloudy
Humidity
44%
Feels like
36°F
Dew Point
16°F
2 PM
36°F
30%
2mph
WNW
30% Chance Light Snow
Humidity
43%
Feels like
36°F
Dew Point
16°F
3 PM
36°F
30%
2mph
WNW
30% Chance Light Snow
Humidity
44%
Feels like
36°F
Dew Point
17°F
4 PM
36°F
30%
1mph
WNW
30% Chance Light Snow
Humidity
46%
Feels like
36°F
Dew Point
17°F
4:50 PM
5 PM
34°F
0%
1mph
W
Cloudy
Humidity
49%
Feels like
34°F
Dew Point
17°F
6 PM
32°F
0%
1mph
WSW
Cloudy
Humidity
53%
Feels like
32°F
Dew Point
17°F
7 PM
31°F
10%
1mph
SSW
Cloudy
Humidity
56%
Feels like
31°F
Dew Point
17°F
8 PM
30°F
10%
1mph
SSW
Mostly Cloudy
Humidity
58%
Feels like
30°F
Dew Point
17°F
9 PM
30°F
10%
1mph
S
Mostly Cloudy
Humidity
59%
Feels like
30°F
Dew Point
17°F
10 PM
29°F
10%
1mph
S
Mostly Cloudy
Humidity
59%
Feels like
29°F
Dew Point
17°F
11 PM
29°F
10%
1mph
SSE
Mostly Cloudy
Humidity
60%
Feels like
29°F
Dew Point
17°F

Rainfall and Snowfall Totals Through Thursday

Flooding Rain, Heavy Snow and Winds Slam Northwest, North-Central U.S.

The atmospheric river this week will keep buffeting the Pacific Northwest with heavy rain, snow, and high winds.

Thursday's Weather Outlook

Thursday's Weather Outlook

How to Measure Snow via NWS

How To Measure Snow

Weekly Drought Map for December 11, 2025

Hit-or-Miss Precipitation Leads to Mixed Drought Results

A person standing in a snowy forest with their back to the camera. They are bundled up in a white hat and a brown jacket. (Image by StockSnap from Pixabay)

Common Cold Weather Illnesses

A strong cold-air-damming event from March 20, 2018.

Cold Air Damming - Cause And Effects

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