Weather Office Sterling, Virginia climate: Climate normals at a NOAA weather station
Weather Office Sterling's normal year runs from 25°F January nights to 87°F July afternoons, with 45.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.0°C, January lows of −4°C, July highs of 31°C, 1,145 mm of precipitation a year.
- NOAA stationWeather Office Sterling
- Station IDUSC00448084
- Location38.98°N 77.49°W
- Elevation288 ft (88 m)
On October 23, the normal high in Weather Office Sterling is 65°F and the normal low 43°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Weather Office Sterling.
- Jan 42° 25°
- Feb 45° 26°
- Mar 54° 33°
- Apr 66° 43°
- May 74° 53°
- Jun 83° 63°
- Jul 87° 67°
- Aug 86° 66°
- Sep 79° 58°
- Oct 68° 45°
- Nov 56° 35°
- Dec 46° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Weather Office Sterling each month?
July is the warmest month, with normal highs of 87°F; January the coldest, with normal lows of 25°F. The most precipitation falls in May (4.92 in), the least in February (2.63 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 42°F | 25°F | 33.4°F | 3.12 | 11 | <1 | 26 | 9 h 40 min |
| February | 45°F | 26°F | 35.7°F | 2.63 | 10 | <1 | 23 | 10 h 40 min |
| March | 54°F | 33°F | 43.4°F | 3.79 | 11 | <1 | 19 | 11 h 50 min |
| April | 66°F | 43°F | 54.5°F | 3.45 | 12 | 1 | 6 | 13 h 10 min |
| May | 74°F | 53°F | 63.8°F | 4.92 | 13 | 1 | 1 | 14 h 20 min |
| June | 83°F | 63°F | 72.6°F | 4.61 | 11 | 6 | <1 | 14 h 50 min |
| July | 87°F | 67°F | 77.2°F | 4.06 | 12 | 12 | <1 | 14 h 40 min |
| August | 86°F | 66°F | 75.7°F | 3.65 | 10 | 9 | <1 | 13 h 40 min |
| September | 79°F | 58°F | 68.5°F | 4.13 | 9 | 3 | <1 | 12 h 30 min |
| October | 68°F | 45°F | 56.6°F | 4.04 | 9 | <1 | 5 | 11 h 20 min |
| November | 56°F | 35°F | 45.6°F | 3.21 | 9 | <1 | 16 | 10 h 10 min |
| December | 46°F | 29°F | 37.4°F | 3.48 | 10 | <1 | 24 | 9 h 30 min |
| Year (annual) | 66°F | 45°F | 55.4°F | 45.09 | 125 | 32 | 119 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 5°C | −4°C | 0.8°C | 79 mm |
| February | 7°C | −3°C | 2.1°C | 67 mm |
| March | 12°C | 1°C | 6.3°C | 96 mm |
| April | 19°C | 6°C | 12.5°C | 88 mm |
| May | 24°C | 12°C | 17.7°C | 125 mm |
| June | 28°C | 17°C | 22.6°C | 117 mm |
| July | 31°C | 20°C | 25.1°C | 103 mm |
| August | 30°C | 19°C | 24.3°C | 93 mm |
| September | 26°C | 14°C | 20.3°C | 105 mm |
| October | 20°C | 7°C | 13.7°C | 103 mm |
| November | 13°C | 2°C | 7.6°C | 82 mm |
| December | 8°C | −2°C | 3.0°C | 88 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Sterling (3 miles away), gets 21 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00448084; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Weather Office Sterling?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, October has the fewest days with rain (9).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00448084.
When is the last frost at Weather Office Sterling?
In Weather Office Sterling, the last spring frost (32°F) comes after April 13 in half of years and after May 1 in one year in ten; the first autumn frost comes before October 26 in half of years and before October 11 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 131 year in 10 after May 1; 9 in 10 after March 29
- First autumn frost, half of years before
- October 261 year in 10 before October 11; 9 in 10 before November 7
NOAA puts the median frost-free season at 195 days, and the season without a hard freeze (28°F) at 218 days.
A hard freeze (28°F) comes after March 31 in half of springs and before November 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Weather Office Sterling in zone 7a in ZIP code 20166, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 7a: the coldest night of a typical year reaches 2°F (28 complete years).
Frost dates for every NOAA station in Virginia · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00448084; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Weather Office Sterling?
In a normal year in Weather Office Sterling, 32 days a year reach 90°F (1 of them 100°F or more), 119 nights fall to 32°F or colder and 125 days bring measurable precipitation.
- Days at 90°F or more
- 32a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 119a normal year
- Days that stay below freezing
- 12high of 32°F or less
- Days with 0.01 inch of precipitation
- 125a normal year
The highest temperature in this station's record (since 1977) is 104°F, on July 23, 2011; the lowest is −19°F, on January 22, 1984.
The wettest calendar year on that record is 1996, with 62.17 in; the snowiest season is 2009–10, with 66.8 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00448084; records: ACIS (NOAA Regional Climate Centers), station USC00448084. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Weather Office Sterling?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds at Weather Office Sterling, 4.1 kWh per square metre a day. July is the sunniest month (80%) and January the cloudiest (70%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 70% | 2.2 |
| February | 70% | 3.0 |
| March | 71% | 4.0 |
| April | 72% | 5.0 |
| May | 73% | 5.6 |
| June | 79% | 6.2 |
| July | 80% | 6.0 |
| August | 79% | 5.4 |
| September | 76% | 4.4 |
| October | 74% | 3.3 |
| November | 75% | 2.5 |
| December | 70% | 1.9 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Weather Office Sterling record?
A normal year at Weather Office Sterling brings 4,714 heating degree days, 12% fewer than the median U.S. place (5,373), and 1,239 cooling degree days, 36% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,865 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 980 | 0 |
| February | 820 | 0 |
| March | 670 | 2 |
| April | 335 | 20 |
| May | 121 | 84 |
| June | 15 | 243 |
| July | 0 | 380 |
| August | 2 | 333 |
| September | 48 | 154 |
| October | 284 | 22 |
| November | 583 | 1 |
| December | 857 | 0 |
| Year (annual) | 4,714 | 1,239 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00448084. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Weather Office Sterling been warmer than normal?
2023 averaged 57.8°F, 2.4°F above the 1991-2020 normal of 55.4°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 56.9°F | +1.5°F | 34.48 |
| 2022 | 55.9°F | +0.5°F | 41.54 |
| 2023 | 57.8°F | +2.4°F | 40.37 |
Over 40 complete years from 1964 to 2023, the station's annual mean temperature rose at a fitted 6.4°F per century (+0.35°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00448084; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Weather Office Sterling's climate compare?
Weather Office Sterling is warmer than 36 of the 81 places with their own NOAA record in Virginia, and wetter than 31. Across the 7,247 U.S. stations with normals, its annual mean of 55.4°F is warmer than 62%.
In the Köppen classification computed from these normals, Weather Office Sterling is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Weather Office Sterling share this climate record?
18 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Ashburn, VA45,551 people · 4 mi N
- Brambleton, VA23,999 people · 2 mi W
- Broadlands, VA14,673 people · 3 mi NW
- Lansdowne, VA12,603 people · 8 mi N
- Loudoun Valley Estates, VA10,323 people · 1 mi W
- Belmont, VA9,525 people · 6 mi N
- Darnestown, MD6,835 people · 12 mi NE
- Poolesville, MD5,856 people · 12 mi N
- Moorefield, VA5,598 people · 2 mi N
- Dulles Town Center, VA5,541 people · 5 mi NE
- University Center, VA4,107 people · 6 mi N
- One Loudoun, VA3,126 people · 5 mi N
- Arcola, VA2,858 people · 3 mi SW
- Goose Creek Village, VA2,519 people · 5 mi NW
- Oak Grove, VA2,452 people · 4 mi E
- Bull Run Mountain Estates, VA1,582 people · 11 mi SW
- Kincora, VA600 people · 5 mi NE
- Aldie, VA168 people · 9 mi W
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Weather Office Sterling's climate
What is the coldest month at Weather Office Sterling?
January, with a normal high of 42°F and a normal low of 25°F. The warmest is July (87°F by day, 67°F at night).
Does it snow at Weather Office Sterling?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Sterling (3 miles away), records 21 inches of snow in a normal year.
What is the rainiest month at Weather Office Sterling?
May, with 4.92 in of precipitation in a normal year; the driest is February with 2.63 in.
What plant hardiness zone is Weather Office Sterling in?
The USDA's 2023 map puts Weather Office Sterling in zone 7a in ZIP code 20166, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 2°F (28 years, 1991-2020): zone 7a.
How late can frost come at Weather Office Sterling?
In half of years the last 32°F night comes after April 13; in one year in ten it comes after May 1. Waiting until May 1 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Virginia climateThe statewide normals and every place in the state
- Sterling, VA2 miles from this station, 55.7°F a year
- Vienna, VA12 miles from this station, 54.0°F a year
- Purcellville, VA17 miles from this station, 54.2°F a year
- Manassas, VA17 miles from this station, 55.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made