Herndon, Pennsylvania Weather
Solstice approaches — longest light. Day 88 of spring. Read this microseason across nine climate regions →
Herndon weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 15Overcast38%—75°61°—
- TuesdayJun 16Overcast——78°52°+3°
- WednesdayJun 17Light Drizzle——80°59°+2°
- ThursdayJun 18Drizzle63%—89°65°+9°
- FridayJun 19Light Drizzle22%—76°59°-13°
- SaturdayJun 20Overcast——75°53°-1°
- SundayJun 21Light Drizzle16%0.09″63°56°-12°
AQI 33 (Good), driven by Ozone. AQI down 13 over the last 6 hours (gradual decline). Ozone at AQI 32 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 14 around 1 PM.
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 32 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 14 around 1 PM.
- Present
- AQI 32
- UV peak
- 3.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 14
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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 5:35 AM
- Moonset
- 8:55 PM
- In sign
- ♊︎ Gemini
Solstice approaches — longest light
Herndon at a glance
- Today vs. normal: 13°F below the seasonal normal for this latitude
- Last frost: April 20 (climatological average for this latitude)
- Microseason: Jun 11–15
- Planting window: Stake and prune tomato suckers. Watch for squash vine borers.
15-Day Forecast — Herndon
- Mon74°60°38%
- Tue78°52°2%
- Wed80°59°8%
- Thu89°65°63%
- Fri76°59°22%
- Sat75°53°4%
- Sun63°56°16%
- Mon75°57°31%
- Tue75°50°31%
- Wed77°55°19%
- Thu81°62°27%
- Fri80°60°39%
- Sat80°53°29%
- Sun83°59°36%
- Mon94°67°36%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of June 15, 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 General Thunderstorms category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
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
- 17830