Gaithersburg, Maryland climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put Gaithersburg's center at January lows of 25°F and July highs of 86°F, a yearly mean of 54.9°F and 44.7 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Rockville (4 miles SE, 440 ft), has January lows of 27°F and July highs of 87°F.
70,686 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 42° 25°
- Feb 45° 27°
- Mar 53° 33°
- Apr 65° 43°
- May 74° 52°
- Jun 82° 61°
- Jul 86° 66°
- Aug 84° 64°
- Sep 78° 58°
- Oct 67° 46°
- Nov 55° 36°
- Dec 46° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
The months above are NOAA's gridded normals at Gaithersburg's center.
What is each month like in Gaithersburg?
NOAA's grid estimates the normals every 5 km or so from the stations around each point, terrain included. It smooths between stations, so night lows at the heart of a large city can run warmer than the grid shows: at five big-city airports we compared, the grid's highs were within about 1°F of the station and its lows 1-6°F cooler. The nearest record's high and low are beside each month.
| Month | High | Low | Mean | Precip. | Rockville high | Rockville low |
|---|---|---|---|---|---|---|
| January | 42°F | 25°F | 33.3°F | 3.06 | 42°F | 27°F |
| February | 45°F | 27°F | 35.8°F | 2.68 | 45°F | 28°F |
| March | 53°F | 33°F | 43.3°F | 3.81 | 54°F | 36°F |
| April | 65°F | 43°F | 54.1°F | 3.50 | 66°F | 46°F |
| May | 74°F | 52°F | 63.2°F | 4.37 | 74°F | 55°F |
| June | 82°F | 61°F | 71.6°F | 4.32 | 82°F | 64°F |
| July | 86°F | 66°F | 76.2°F | 4.34 | 87°F | 69°F |
| August | 84°F | 64°F | 74.2°F | 3.76 | 85°F | 67°F |
| September | 78°F | 58°F | 67.5°F | 4.30 | 78°F | 60°F |
| October | 67°F | 46°F | 56.3°F | 3.77 | 66°F | 48°F |
| November | 55°F | 36°F | 45.7°F | 3.23 | 56°F | 38°F |
| December | 46°F | 29°F | 37.4°F | 3.61 | 46°F | 31°F |
In metric: a yearly mean of 12.7°C, January lows of −4°C, July highs of 30°C and 1,136 mm of precipitation a year.
Source: NOAA NCEI U.S. Monthly Gridded Climate Normals 1991-2020 (nClimGrid, accession 0245564); NOAA NCEI 1991-2020 station normals. The grid cell holding the city's Census center point.
What do the station records around Gaithersburg say?
Each row is a NOAA station's own 1991-2020 normals, with the snow and frost dates the grid does not give. A record downhill or nearer the coast than the city can run warmer, one uphill cooler: compare the elevations.
| Record | Where | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Rockville1 mi NE | 4 mi SE | 440 ft | 56.2°F | 27°F | 87°F | 41.3 | – | April 1 |
| Damascus3 mi SSW | 8 mi N | 700 ft | 54.0°F | 25°F | 84°F | 47.9 | 31 | April 14 |
| Dalecarlia Reservoir | 15 mi S | 150 ft | 56.2°F | 26°F | 88°F | 48.5 | 6 | April 9 |
Source: NOAA NCEI 1991-2020 U.S. Climate Normals; place center and population: Census Bureau 2024. Last frost: the median last spring date of 32°F.
How much snow, how late a frost, what zone and how much sun in Gaithersburg?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Rockville (4 miles SE, 440 ft). NOAA publishes no snowfall normal for it; the nearest record that has one, Damascus (8 miles N), gets 31 inches a year. The last spring frost (32°F) comes after April 1 in half of years and the first autumn frost before November 6. Its record high is 104°F (1918) and its record low −13°F (1985) (kept since 1907).
The USDA's 2023 Plant Hardiness Zone Map puts Gaithersburg in zone 7b across its 3 ZIP code areas.
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (4.0 kWh per square metre a day, NASA POWER 2001-2020); July is the sunniest month (79%) and January the cloudiest (65%).
Rockville's page has its months, frost probabilities, records by month and recent years. NOAA's grid has monthly figures only, so there are no day-by-day month pages for Gaithersburg; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00187705; records: ACIS; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; sunshine: NASA POWER.
How does the climate vary across Gaithersburg, ZIP code by ZIP code?
3 ZIP code areas lie wholly or partly in Gaithersburg. On NOAA's grid 20878 is the warmest (55.2°F a year) and 20879 the coolest (54.9°F), so the city is nearly uniform. Each row also names the nearest station record and its frost dates.
| ZIP code | Zone | Year | Jan low | Jul high | Precip. | Nearest record | Last frost | First frost |
|---|---|---|---|---|---|---|---|---|
| 20877 | 7b | 54.9°F | 25°F | 86°F | 44.7 | Rockville (4 mi) | April 1 | November 6 |
| 20878 | 7b | 55.2°F | 25°F | 86°F | 44.2 | Rockville (6 mi) | April 1 | November 6 |
| 20879 | 7b | 54.9°F | 25°F | 86°F | 45.1 | Rockville (5 mi) | April 1 | November 6 |
Source: Census Bureau 2020 ZCTA-to-place relationship file and ZCTA centers; NOAA NCEI gridded and station normals, 1991-2020. A ZIP area counts when at least a tenth of its land (and 0.5 km²) is in the city; its figures are the grid cell at its center; frost dates are the nearest record's medians of 32°F.