The year at a glance
Averages from 30 years of climate history, 1991-2020
| Herndon | Metric | McNair |
|---|---|---|
| 205 days | Sunny daysclear or partly cloudy skies | 205 days |
| 42 in | Precipitationper year | 42 in |
| 119 days | Wet daysrain or snow per year | 119 days |
| 21 in | Snowfallper year | 21 in |
| 29 days | Hot daysabove 90 °F | 32 days |
| 106 days | Freezing nightsat or below 32 °F | 105 days |
| 69% | Humidityaverage relative | 69% |
| 55 °F | Average temperatureyear round | 56 °F |
Monthly temperatures
Average daily high and low for each month, in °F. The gap between the two lines is what an ordinary day feels like across the year.
Daily highs
Daily lows
View monthly temperatures as a table
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Herndon high | 42 | 46 | 54 | 66 | 74 | 82 | 87 | 86 | 79 | 67 | 56 | 46 |
| McNair high | 42 | 46 | 55 | 67 | 75 | 83 | 87 | 86 | 79 | 68 | 56 | 46 |
| Herndon low | 25 | 26 | 33 | 43 | 53 | 62 | 67 | 65 | 58 | 45 | 35 | 29 |
| McNair low | 25 | 26 | 33 | 43 | 53 | 62 | 67 | 65 | 58 | 45 | 35 | 29 |
Monthly precipitation
Total rain plus melted snow for each month, in inches. Taller bars mean wetter months.
View monthly precipitation as a table
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Herndon | 3.0 | 2.8 | 3.8 | 3.4 | 3.8 | 3.4 | 3.9 | 3.3 | 4.3 | 3.4 | 3.0 | 3.5 |
| McNair | 3.0 | 2.8 | 3.8 | 3.4 | 3.8 | 3.4 | 3.9 | 3.3 | 4.3 | 3.4 | 3.0 | 3.5 |
Monthly sunny days
Days each month with clear or partly cloudy skies, so compare the same month between cities.
View monthly sunny days as a table
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Herndon | 16 | 15 | 16 | 16 | 16 | 17 | 19 | 19 | 18 | 20 | 18 | 16 |
| McNair | 16 | 15 | 16 | 16 | 16 | 17 | 19 | 19 | 18 | 20 | 18 | 16 |
Keep comparing
Nearby cities and popular picks for each side of this matchup. Any two cities can be compared from the home page.
Herndon vs another city
- Herndon vs Hutchison, VA
- Herndon vs Dranesville, VA
- Herndon vs Sterling, VA
- Herndon vs Reston, VA
- Herndon vs Floris, VA
- Herndon vs New York, NY
- Herndon vs Los Angeles, CA
- Herndon vs Chicago, IL
- Herndon vs Houston, TX
- Herndon vs Phoenix, AZ
- Herndon vs Philadelphia, PA
McNair vs another city
- McNair vs Hutchison, VA
- McNair vs Floris, VA
- McNair vs Franklin Farm, VA
- McNair vs Reston, VA
- McNair vs Sterling, VA
- McNair vs New York, NY
- McNair vs Los Angeles, CA
- McNair vs Chicago, IL
- McNair vs Houston, TX
- McNair vs Phoenix, AZ
- McNair vs Philadelphia, PA
About this data
Every figure on this page is a 30 year average computed from daily climate history for 1991-2020, using each city's own coordinates. Wet days count days with measurable precipitation, calibrated against the wet day counts in NOAA's published climate normals. Sunny days count clear plus partly cloudy days, defined as average cloud cover of 63 percent or less and calibrated against NOAA's published sky cover tables. Snowfall figures are model estimates anchored to NOAA station measurements near each city.
Weather data by Open-Meteo.com (CC BY 4.0). Contains modified Copernicus Climate Change Service information (ERA5, ERA5-Land).