Herndon, Virginia Weather
Cicadas claim the afternoon. Day 15 of summer. Read this microseason across nine climate regions →
Herndon weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Light Drizzle48%0.02″100°75°—
- SundayJul 5Overcast38%—95°72°-5°
- MondayJul 6Light Showers80%0.73″90°74°-5°
- TuesdayJul 7Heavy Drizzle80%0.01″81°70°-9°
- WednesdayJul 8Light Drizzle37%0.02″77°68°-4°
- ThursdayJul 9Overcast11%—95°68°+18°
- FridayJul 10Light Drizzle45%—97°74°+2°
AQI 69 (Moderate), driven by PM2.5. AQI down 44 over the last 6 hours — air quality is improving sharply. PM2.5 at 14.7 µg/m³, PM10 at 15.1 µg/m³ — typical background levels with no transport signature.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 34 now. With UV 0.0 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 8 around 1 PM.
- Present
- AQI 34
- UV peak
- 0.0 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 8
PM × Wind × Precip
PM2.5 at 14.7 µg/m³, PM10 at 15.1 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.97
- Wind
- light
- Recent rain
- 1h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:26 PM
- Moonset
- 11:19 AM
- In sign
- ♓︎ Pisces
Cicadas claim the afternoon
Herndon at a glance
- Today vs. normal: 75°F — typical for the season
- Last frost: April 10 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP codes: 20170, 20171
16-Day Forecast — Herndon
- Sat100°75°48%
- Sun95°72°38%
- Mon90°74°80%
- Tue81°70°80%
- Wed77°68°37%
- Thu95°68°11%
- Fri97°74°45%
- Sat84°69°37%
- Sun81°66°25%
- Mon86°61°19%
- Tue92°65°17%
- Wed90°68°23%
- Thu90°66°29%
- Fri91°71°27%
- Sat91°71°30%
- Sun87°69°36%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — Herndon
SPC has placed Herndon in the Slight Risk category for severe thunderstorms tomorrow.
- TODAYMRGLMarginal Risk
- TOMORROWSLGTSlight Risk
- DAY 3TSTMGeneral Thunderstorms
Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
ZIP codes in Herndon
- 20170
- 20172
- 22095