Weather World
Potomac River Reservoir Monthly Climate Averages
January |
February |
March |
April |
May |
June |
July |
August |
September |
October |
November |
December |
| Hi 40°F Lo 30°F | Hi 43°F Lo 32°F | Hi 51°F Lo 39°F | Hi 62°F Lo 48°F | Hi 71°F Lo 58°F | Hi 80°F Lo 67°F | Hi 85°F Lo 73°F | Hi 83°F Lo 71°F | Hi 77°F Lo 65°F | Hi 66°F Lo 55°F | Hi 55°F Lo 44°F | Hi 46°F Lo 37°F |
| 10 mph | 10 mph | 10 mph | 10 mph | 8 mph | 8 mph | 7 mph | 7 mph | 8 mph | 9 mph | 10 mph | 10 mph |
| 3.8 in | 4.6 in | 4.1 in | 4.3 in | 5.2 in | 4.9 in | 5.8 in | 4.9 in | 5.5 in | 5.1 in | 3.5 in | 4.8 in |
| 71% | 73% | 72% | 72% | 77% | 75% | 74% | 73% | 74% | 73% | 70% | 74% |
| 42% | 46% | 44% | 42% | 44% | 34% | 33% | 34% | 36% | 36% | 35% | 44% |
| 30.1 in | 30.1 in | 30.1 in | 30.0 in | 30.0 in | 29.9 in | 30.0 in | 30.0 in | 30.0 in | 30.1 in | 30.1 in | 30.1 in |
| 23 | 18 | 23 | 24 | 22 | 21 | 21 | 22 | 23 | 25 | 25 | 24 |
| 6 | 7 | 7 | 6 | 9 | 9 | 10 | 9 | 7 | 6 | 5 | 6 |
| 2 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 2 | 2 | 3 | 4 | 5 | 6 | 6 | 6 | 5 | 3 | 2 | 2 |
| 188 | 155 | 174 | 179 | 182 | 223 | 238 | 228 | 209 | 202 | 212 | 181 |
January |
February |
March |
April |
May |
June |
July |
August |
September |
October |
November |
December |
| Hi 5°C Lo -1°C | Hi 6°C Lo 0°C | Hi 11°C Lo 4°C | Hi 17°C Lo 9°C | Hi 21°C Lo 15°C | Hi 26°C Lo 20°C | Hi 29°C Lo 23°C | Hi 28°C Lo 22°C | Hi 25°C Lo 19°C | Hi 19°C Lo 13°C | Hi 13°C Lo 6°C | Hi 8°C Lo 3°C |
| 16 km/h | 16 km/h | 17 km/h | 16 km/h | 14 km/h | 13 km/h | 11 km/h | 11 km/h | 13 km/h | 15 km/h | 16 km/h | 15 km/h |
| 97 mm | 115 mm | 105 mm | 108 mm | 133 mm | 125 mm | 146 mm | 124 mm | 141 mm | 129 mm | 89 mm | 121 mm |
| 71% | 73% | 72% | 72% | 77% | 75% | 74% | 73% | 74% | 73% | 70% | 74% |
| 42% | 46% | 44% | 42% | 44% | 34% | 33% | 34% | 36% | 36% | 35% | 44% |
| 1019 mb | 1019 mb | 1018 mb | 1016 mb | 1016 mb | 1014 mb | 1015 mb | 1016 mb | 1017 mb | 1018 mb | 1020 mb | 1020 mb |
| 23 | 18 | 23 | 24 | 22 | 21 | 21 | 22 | 23 | 25 | 25 | 24 |
| 6 | 7 | 7 | 6 | 9 | 9 | 10 | 9 | 7 | 6 | 5 | 6 |
| 2 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 2 | 2 | 3 | 4 | 5 | 6 | 6 | 6 | 5 | 3 | 2 | 2 |
| 188 | 155 | 174 | 179 | 182 | 223 | 238 | 228 | 209 | 202 | 212 | 181 |
| Month |
| Avg. Temperatures |
| Avg. Wind Speed |
| Avg. Precipitation |
| Average Humidity |
| Avg. Cloud Cover |
| Pressure Average |
| Average Dry Days |
| Avg. Precip. Days |
| Avg. Snow Days |
| Average Fog Days |
| Average UV Index |
| Avg. Hours of Sun |
Averages are based on historical weather data from the past 10 years.