Frieda Fromm-Reichmann Cottage · Photo: Farragutful · CC BY-SA 4.0Rockville’s winters are milder and less snowy than most of the U.S.
A typical July afternoon reaches 86°, a January night drops to 25°, and about 6 inches of snow falls in a normal winter.
A year in Rockville at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rockville’s climate
Compared with towns across the U.S., with Rockville’s place in Maryland beside it.
What a year in Rockville 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, 1.2 miles from the city’s center point, at about the same height.
The 2023 USDA map puts Rockville’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 6 inches of snow a winter
Snow, measured at Dalecarlia Reservoir, MD, falls mostly in January. Precipitation (rain plus melted snow) adds up to 45 inches a year; July is the wettest month and February the driest. Rain or snow falls on about 123 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Rockville
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 Rockville’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. 19 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Rockville from natural hazards, river flooding is the largest share (47%); heat waves, cold waves, winter storms and ice storms together are 17%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Rockville and its neighbors
Every town next door is within a degree of Rockville in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Rockville’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 |
|---|---|---|---|---|
| Rockville, MD | 25° | 86° | 45" | 5.8" |
| Ironton, OH | 24° | 87° | 44" | 6.2" |
| Ashland, KY | 24° | 87° | 45" | 6.2" |
| Bloomingdale, TN | 27° | 87° | 45" | 5.1" |
| Huntington, WV | 25° | 87° | 46" | 10" |
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 Rockville averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.0°).
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 Rockville compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Rockville’s place among Maryland’s.
Rockville weather by month
Highs, lows and precipitation from NOAA’s grid at Rockville’s center; snow, wet days and snow on the ground from Dalecarlia Reservoir, MD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 42° | 25° | 3.1" | 2.9" | 10 | 2 | 26° – 41° |
| February | 45° | 27° | 2.7" | 1.4" | 9 | 2 | 25° – 44° |
| March | 54° | 33° | 3.8" | 0.7" | 12 | 1 | 38° – 53° |
| April | 65° | 43° | 3.5" | 0.0" | 11 | 0 | 51° – 60° |
| May | 74° | 53° | 4.4" | 0.0" | 12 | 0 | 59° – 70° |
| June | 82° | 62° | 4.3" | 0.0" | 10 | 0 | 68° – 76° |
| July | 86° | 67° | 4.5" | 0.0" | 10 | 0 | 72° – 80° |
| August | 84° | 65° | 3.8" | 0.0" | 10 | 0 | 70° – 78° |
| September | 78° | 58° | 4.3" | 0.0" | 10 | 0 | 65° – 72° |
| October | 67° | 46° | 3.8" | 0.0" | 9 | 0 | 53° – 63° |
| November | 56° | 36° | 3.2" | 0.0" | 9 | 0 | 40° – 51° |
| December | 46° | 30° | 3.7" | 0.8" | 11 | 1 | 28° – 48° |
| Year | 65° | 45° | 44.9" | 5.8" | 123 | 6 |
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 Rockville’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 Rockville’s center.
- Snow: Dalecarlia Reservoir, MD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Rockville 1 Ne, MD, 1.2 miles from the city’s center point, 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 Rockville’s climate
What is the weather like in Rockville?
A typical July afternoon reaches 86°, a January night drops to 25°, and about 6 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 Rockville 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 26°.
How much snow does Rockville get?
About 5.8 inches in a normal winter at Dalecarlia Reservoir, MD, most of it in January, with snow on the ground about 6 days a year.
How hot does it get in Rockville?
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 Rockville?
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 Rockville 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 Rockville?
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 Rockville 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 Rockville.
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.