Sterling, Virginia climate: Normal weather by month, frost dates and records
Sterling's normal year runs from 25°F January nights to 88°F July afternoons, with 43.2 inches of precipitation and 21 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.2°C, January lows of −4°C, July highs of 31°C, 1,098 mm of precipitation a year.
- NOAA stationWashington Dulles International Airport
- Station IDUSW00093738
- Location38.94°N 77.46°W
- Elevation290 ft (88 m)
- From the center5 miles
- Population (census place)31,251
On October 14, the normal high in Sterling is 69°F and the normal low 46°F, and the chance of measurable rain or snow is 27%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sterling.
- Jan 43° 25°
- Feb 46° 27°
- Mar 55° 34°
- Apr 67° 43°
- May 75° 53°
- Jun 83° 62°
- Jul 88° 67°
- Aug 86° 65°
- Sep 79° 58°
- Oct 68° 45°
- Nov 57° 36°
- Dec 47° 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 in Sterling each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 25°F. The most precipitation falls in May (4.72 in), the least in February (2.61 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 43°F | 25°F | 33.9°F | 2.94 | 6.9 | 10 | <1 | 24 | 9 h 40 min |
| February | 46°F | 27°F | 36.4°F | 2.61 | 7.0 | 9 | <1 | 21 | 10 h 40 min |
| March | 55°F | 34°F | 44.2°F | 3.50 | 3.9 | 11 | <1 | 15 | 11 h 50 min |
| April | 67°F | 43°F | 55.0°F | 3.47 | 0.1 | 11 | <1 | 4 | 13 h 10 min |
| May | 75°F | 53°F | 64.0°F | 4.72 | 0.0 | 13 | 1 | <1 | 14 h 20 min |
| June | 83°F | 62°F | 72.5°F | 4.30 | 0.0 | 11 | 6 | <1 | 14 h 50 min |
| July | 88°F | 67°F | 77.2°F | 4.15 | 0.0 | 11 | 13 | <1 | 14 h 40 min |
| August | 86°F | 65°F | 75.7°F | 3.53 | 0.0 | 9 | 9 | <1 | 13 h 40 min |
| September | 79°F | 58°F | 68.6°F | 3.94 | 0.0 | 9 | 3 | <1 | 12 h 30 min |
| October | 68°F | 45°F | 56.6°F | 3.65 | 0.0 | 8 | <1 | 2 | 11 h 10 min |
| November | 57°F | 36°F | 46.0°F | 3.13 | 0.3 | 9 | <1 | 13 | 10 h 10 min |
| December | 47°F | 29°F | 37.7°F | 3.30 | 2.8 | 10 | <1 | 22 | 9 h 30 min |
| Year (annual) | 66°F | 45°F | 55.7°F | 43.24 | 21.0 | 121 | 33 | 102 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 6°C | −4°C | 1.1°C | 75 mm | 18 cm |
| February | 8°C | −3°C | 2.4°C | 66 mm | 18 cm |
| March | 13°C | 1°C | 6.8°C | 89 mm | 10 cm |
| April | 19°C | 6°C | 12.8°C | 88 mm | 0 cm |
| May | 24°C | 12°C | 17.8°C | 120 mm | 0 cm |
| June | 28°C | 17°C | 22.5°C | 109 mm | 0 cm |
| July | 31°C | 19°C | 25.1°C | 105 mm | 0 cm |
| August | 30°C | 18°C | 24.3°C | 90 mm | 0 cm |
| September | 26°C | 14°C | 20.3°C | 100 mm | 0 cm |
| October | 20°C | 7°C | 13.7°C | 93 mm | 0 cm |
| November | 14°C | 2°C | 7.8°C | 80 mm | 1 cm |
| December | 8°C | −2°C | 3.2°C | 84 mm | 7 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00093738; 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.
When is the best weather to visit 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 (8).
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 USW00093738.
When is the last frost in Sterling?
In Sterling, the last spring frost (32°F) comes after April 15 in half of years and after April 30 in one year in ten; the first autumn frost comes before October 24 in half of years and before October 10 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 151 year in 10 after April 30; 9 in 10 after March 31
- First autumn frost, half of years before
- October 241 year in 10 before October 10; 9 in 10 before November 5
NOAA puts the median frost-free season at 194 days, and the season without a hard freeze (28°F) at 218 days.
A hard freeze (28°F) comes after April 1 in half of springs and before November 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sterling in zone 7b in ZIP code 20164. By the map's own method, the average of each year's coldest night over 1991-2020, Sterling's NOAA station is in zone 7a: the coldest night of a typical year reaches 4°F (30 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Virginia · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00093738; 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 in Sterling?
In a normal year in Sterling, 33 days a year reach 90°F (1 of them 100°F or more), 102 nights fall to 32°F or colder and 121 days bring measurable precipitation.
- Days at 90°F or more
- 33a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 102a normal year
- Days that stay below freezing
- 11high of 32°F or less
- Days with 0.01 inch of precipitation
- 121a normal year
- Days with 1 inch of snow or more
- 5a normal year
The highest temperature in this station's record (since 1960) is 105°F, on July 22, 2011; the lowest is −18°F, on January 22, 1984.
The wettest calendar year on that record is 2018, with 66.74 in; the snowiest season is 2009–10, with 73.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00093738; records: ACIS (NOAA Regional Climate Centers), station USW00093738. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Sterling, and how clear are its skies?
The summer (June-August) dew point averages 64°F. The muggiest month is July, with an average dew point of 65°F, above the 65°F at which most people call the air sticky; the driest air comes in January (22°F). February is the windiest month (8.7 mph on average), and September has the most clear or nearly clear hours (43%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 22°F | 61% | 46% | 7.6 mph | 35% | 36% |
| February | 26°F | 60% | 45% | 8.7 mph | 32% | 39% |
| March | 35°F | 57% | 41% | 8.6 mph | 34% | 36% |
| April | 46°F | 62% | 45% | 7.4 mph | 33% | 33% |
| May | 58°F | 69% | 51% | 6.4 mph | 35% | 30% |
| June | 64°F | 69% | 50% | 5.8 mph | 33% | 22% |
| July | 65°F | 70% | 51% | 5.6 mph | 35% | 24% |
| August | 63°F | 71% | 50% | 5.6 mph | 37% | 23% |
| September | 54°F | 73% | 51% | 6.0 mph | 43% | 27% |
| October | 40°F | 67% | 47% | 6.6 mph | 41% | 30% |
| November | 31°F | 66% | 50% | 7.0 mph | 36% | 34% |
| December | 25°F | 65% | 51% | 7.4 mph | 34% | 37% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00093738. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Sterling?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around 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 much heating and cooling does Sterling need?
A normal year in Sterling brings 4,604 heating degree days, 14% fewer than the median U.S. place (5,373), and 1,233 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 3,886 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 964 | 0 |
| February | 801 | 0 |
| March | 647 | 2 |
| April | 320 | 20 |
| May | 115 | 84 |
| June | 13 | 238 |
| July | 0 | 378 |
| August | 1 | 334 |
| September | 45 | 153 |
| October | 284 | 22 |
| November | 570 | 1 |
| December | 845 | 0 |
| Year (annual) | 4,604 | 1,233 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00093738. 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.
Has Sterling been warmer than normal lately?
2025 averaged 56.4°F, 0.7°F above the 1991-2020 normal of 55.7°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 57.6°F | +1.9°F | 34.96 | 9.6 |
| 2022 | 56.4°F | +0.7°F | 40.76 | 15.8 |
| 2023 | 58.6°F | +2.9°F | 34.78 | 0.9 |
| 2024 | 58.8°F | +3.1°F | 34.37 | 11.3 |
| 2025 | 56.4°F | +0.7°F | 30.17 | 17.4 |
Over 53 complete years from 1964 to 2025, the station's annual mean temperature rose at a fitted 4.5°F per century (+0.25°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00093738; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Sterling's climate compare?
Sterling is warmer than 39 of the other 80 places with their own NOAA record in Virginia, and wetter than 16. Across the 7,247 U.S. stations with normals, its annual mean of 55.7°F is warmer than 63%.
In the Köppen classification computed from these normals, 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 Sterling share this climate record?
13 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.
- Centreville, VAalso near: Manassas (8 mi, 55.5°F a year); Vienna (9 mi, 54.0°F a year)71,885 people · 7 mi S
- South Riding, VA34,200 people · 3 mi SW
- Herndon, VA25,180 people · 5 mi NE
- Chantilly, VA23,744 people · 4 mi S
- McNair, VA22,451 people · 3 mi E
- Franklin Farm, VA18,509 people · 4 mi SE
- Stone Ridge, VA16,340 people · 5 mi W
- Greenbriar, VA7,989 people · 6 mi SE
- Bull Run, VA7,513 people · 7 mi S
- Floris, VA7,135 people · 3 mi E
- Hutchison, VA6,936 people · 3 mi NE
- Navy, VA3,787 people · 5 mi SE
- Sully Square, VA2,668 people · 2 mi SE
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 Sterling's climate
What is the coldest month in Sterling?
January, with a normal high of 43°F and a normal low of 25°F. The warmest is July (88°F by day, 67°F at night).
Does it snow in Sterling?
Yes: 21 inches in a normal year, falling on 10 days with 0.1 inch or more, the most in February (7.0 inches).
What is the rainiest month in Sterling?
May, with 4.72 in of precipitation in a normal year; the driest is February with 2.61 in.
What plant hardiness zone is Sterling in?
The USDA's 2023 map puts Sterling in zone 7b in ZIP code 20164. By the same method at Sterling's NOAA station, the coldest night of a typical year reaches 4°F (30 years, 1991-2020): zone 7a.
How late can frost come in Sterling?
In half of years the last 32°F night comes after April 15; in one year in ten it comes after April 30. Waiting until April 30 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Sterling in OctoberThis month day by day, its records and recent years
- Virginia climateThe statewide normals and every place in the state
- Weather Office Sterling, VA2 miles from this station, 55.4°F a year
- Vienna, VA10 miles from this station, 54.0°F a year
- Manassas, VA14 miles from this station, 55.5°F a year
- Dalecarlia Reservoir, MD19 miles from this station, 56.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made