Photo: TwoScarsUp · CC BY-SA 4.0In North Potomac, July heat, January chill and rainfall all sit near the middle of U.S. towns
High summer brings afternoon highs near 86°. The gap between a January night and a July afternoon is 61°. Winters are mild: January nights here are milder than in 64% of U.S. towns. Garden planting can start around April 1; autumn frost returns near November 6.
A year in North Potomac at a glance
Each month’s typical high and low, and what it brings.
What stands out about North Potomac’s climate
Compared with towns across the U.S., with North Potomac’s place in Maryland beside it.
What a year in North Potomac feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 219 frost-free days a year
In half of years the last 32° night comes by April 1 and the first by November 6. Frost and day counts come from NOAA’s station at Rockville 1 Ne, MD, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts North Potomac’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 7°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 33 inches of snow a winter
Snow, measured at Clarksburg 2.1 Ne, MD, falls mostly in January. Precipitation (rain plus melted snow) adds up to 44 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 137 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in North Potomac
78% of the work is heating. Months averaging under 55° run from November through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Rockville 1 Ne, MD.
Living with North Potomac’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
219 frost-free days in zone 7b. The last frost comes by Apr 1 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 6.
Months with highs of 62–84° and lows of 40° or more: April, May, June, September and October. 15 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in North Potomac from natural hazards, river flooding is the largest share (63%); heat waves, cold waves, winter storms and ice storms together are 13%. Normals are averages; the hazards page covers the extremes.
Natural hazards →North Potomac and its neighbors
Every town next door is within a degree of North Potomac in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like North Potomac’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| North Potomac, MD | 25° | 86° | 44" | 33" |
| Charleston, WV | 25° | 87° | 46" | 32" |
| Elizabeth, NJ | 26° | 86° | 47" | 32" |
| Mount Vernon, NY | 26° | 86° | 47" | 33" |
| Fort Thomas, KY | 24° | 87° | 45" | 23" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in North Potomac averaged 1.8° warmer than the 1900s. The biggest change is in December (+2.9°).
A bigger shift than in 76% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How North Potomac compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with North Potomac’s place among Maryland’s.
North Potomac weather by month
Highs, lows and precipitation from NOAA’s grid at North Potomac’s center; snow, wet days and snow on the ground from Clarksburg 2.1 Ne, MD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 42° | 25° | 3.1" | 10.6" | 11 | 8 | 25° – 41° |
| February | 45° | 27° | 2.6" | 7.9" | 11 | 9 | 25° – 44° |
| March | 54° | 34° | 3.8" | 6.8" | 11 | 5 | 38° – 53° |
| April | 66° | 43° | 3.5" | 0.0" | 13 | 0 | 51° – 60° |
| May | 74° | 53° | 4.4" | 0.0" | 15 | 0 | 59° – 70° |
| June | 82° | 62° | 4.3" | 0.0" | 12 | 0 | 68° – 76° |
| July | 86° | 67° | 4.3" | 0.0" | 11 | 0 | 72° – 80° |
| August | 85° | 65° | 3.7" | 0.0" | 12 | 0 | 70° – 78° |
| September | 78° | 58° | 4.2" | 0.0" | 10 | 0 | 65° – 72° |
| October | 67° | 46° | 3.7" | 0.3" | 11 | 0 | 53° – 63° |
| November | 56° | 36° | 3.2" | 0.7" | 9 | 1 | 40° – 51° |
| December | 46° | 30° | 3.6" | 6.3" | 11 | 4 | 28° – 48° |
| Year | 65° | 45° | 44.2" | 32.6" | 137 | 27 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 28° to 48°. September is the most reliable, staying within 7°.
Where North Potomac’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at North Potomac’s center.
- Snow: Clarksburg 2.1 Ne, MD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Rockville 1 Ne, MD, 5 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about North Potomac’s climate
What is the weather like in North Potomac?
A typical July afternoon reaches 86°, a January night drops to 25°, and about 33 inches of snow falls in a normal winter. Milder January nights than 64% of U.S. towns; hotter July afternoons than 58% of U.S. towns.
How cold does it get in North Potomac in winter?
January nights average 25°. About 86 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 25°.
How much snow does North Potomac get?
About 33 inches in a normal winter at Clarksburg 2.1 Ne, MD, most of it in January, with snow on the ground about 27 days a year.
How hot does it get in North Potomac?
July, with a typical high of 86° and a low of 67°. About 23 days a year reach 90° (Rockville 1 Ne, MD).
When is the first and last frost in North Potomac?
In half of years the last spring frost (32°) comes by April 1 and the first fall frost by November 6, about 219 frost-free days, at Rockville 1 Ne, MD.
What growing zone is North Potomac in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 7°.
What is the best time of year to visit North Potomac?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, June, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is North Potomac getting warmer?
Yes: 1991–2020 averaged 1.8° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 76% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in North Potomac.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.