Bethesda, Maryland climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put Bethesda's center at January lows of 26°F and July highs of 87°F, a yearly mean of 55.9°F and 44.7 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Washington (11 miles SE, 10 ft), has January lows of 30°F and July highs of 90°F.
67,403 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 43° 26°
- Feb 46° 28°
- Mar 54° 34°
- Apr 66° 44°
- May 75° 54°
- Jun 83° 63°
- Jul 87° 68°
- Aug 85° 66°
- Sep 79° 59°
- Oct 68° 47°
- Nov 56° 37°
- Dec 47° 30°
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 Bethesda's center.
What is each month like in Bethesda?
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. | Washington high | Washington low |
|---|---|---|---|---|---|---|
| January | 43°F | 26°F | 34.4°F | 2.99 | 45°F | 30°F |
| February | 46°F | 28°F | 36.8°F | 2.67 | 48°F | 32°F |
| March | 54°F | 34°F | 44.3°F | 3.75 | 57°F | 39°F |
| April | 66°F | 44°F | 55.1°F | 3.42 | 68°F | 48°F |
| May | 75°F | 54°F | 64.0°F | 4.30 | 77°F | 58°F |
| June | 83°F | 63°F | 72.7°F | 4.31 | 85°F | 68°F |
| July | 87°F | 68°F | 77.4°F | 4.52 | 90°F | 72°F |
| August | 85°F | 66°F | 75.5°F | 3.76 | 88°F | 71°F |
| September | 79°F | 59°F | 68.7°F | 4.34 | 81°F | 64°F |
| October | 68°F | 47°F | 57.3°F | 3.85 | 69°F | 52°F |
| November | 56°F | 37°F | 46.6°F | 3.14 | 58°F | 42°F |
| December | 47°F | 30°F | 38.5°F | 3.67 | 49°F | 35°F |
In metric: a yearly mean of 13.3°C, January lows of −3°C, July highs of 31°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 Bethesda 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 |
|---|---|---|---|---|---|---|---|---|
| WashingtonWashington Reagan Airport | 11 mi SE | 10 ft | 59.3°F | 30°F | 90°F | 41.8 | 14 | March 24 |
| Dalecarlia Reservoir | 3 mi S | 150 ft | 56.2°F | 26°F | 88°F | 48.5 | 6 | April 9 |
| Rockville1 mi NE | 8 mi N | 440 ft | 56.2°F | 27°F | 87°F | 41.3 | – | April 1 |
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 Bethesda?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Washington (11 miles SE, 10 ft). It gets 14 inches of snow in a normal year. The last spring frost (32°F) comes after March 24 in half of years and the first autumn frost before November 18. Its record high is 106°F (1930) and its record low −15°F (1899), on the National Weather Service's long record for the area (kept since 1871).
The USDA's 2023 Plant Hardiness Zone Map puts Bethesda in zone 7b across its 5 ZIP code areas.
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (4.1 kWh per square metre a day, NASA POWER 2001-2020); July is the sunniest month (80%) and January the cloudiest (70%).
Washington'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 Bethesda; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USW00013743; 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 Bethesda, ZIP code by ZIP code?
5 ZIP code areas lie wholly or partly in Bethesda. On NOAA's grid 20816 is the warmest (56.3°F a year) and 20889 the coolest (55.8°F), a spread of 0.5°F. 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 |
|---|---|---|---|---|---|---|---|---|
| 20814 | 7b | 55.8°F | 26°F | 87°F | 44.7 | Dalecarlia Reservoir (5 mi) | April 9 | October 31 |
| 20815 | 7b | 56.0°F | 26°F | 87°F | 44.8 | Dalecarlia Reservoir (4 mi) | April 9 | October 31 |
| 20816 | 7b | 56.3°F | 26°F | 88°F | 44.5 | Dalecarlia Reservoir (1 mi) | April 9 | October 31 |
| 20817 | 7b | 56.1°F | 26°F | 88°F | 44.2 | Dalecarlia Reservoir (5 mi) | April 9 | October 31 |
| 20889 | 7b | 55.8°F | 26°F | 87°F | 44.7 | Dalecarlia Reservoir (5 mi) | April 9 | October 31 |
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.