Johnstown, Pennsylvania Weather
Cicadas claim the afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Johnstown weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Heavy Showers38%1.4″94°66°—
- SundayJul 5Rain84%0.23″88°70°-6°
- MondayJul 6T-storm w/ Hail84%0.05″80°66°-8°
- TuesdayJul 7Light Drizzle41%0.01″78°63°-2°
- WednesdayJul 8Light Drizzle14%—84°58°+6°
- ThursdayJul 9Overcast46%—87°64°+3°
- FridayJul 10Light Drizzle51%—80°67°-7°
AQI 58 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 13.4 µg/m³ (AQI 59) with a 0.95 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in calm air, not road dust.
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 37 now. With UV 3.7 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 18 around 1 PM.
- Present
- AQI 37
- UV peak
- 3.7 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 18
PM × Wind × Precip
PM2.5 at 13.4 µg/m³ (AQI 59) with a 0.95 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.95
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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
- 11:10 PM
- Moonset
- 10:19 AM
- In sign
- ♓︎ Pisces
Cicadas claim the afternoon
Johnstown at a glance
- Today vs. normal: 3°F above the seasonal normal for this latitude
- Last frost: April 18 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP codes: 15901, 15902, 15904, 15905, 15906, 15909
16-Day Forecast — Johnstown
- Sat94°66°38%
- Sun88°70°84%
- Mon80°66°84%
- Tue78°63°41%
- Wed84°58°14%
- Thu87°64°46%
- Fri80°67°51%
- Sat84°67°44%
- Sun80°66°30%
- Mon72°61°20%
- Tue75°61°20%
- Wed82°65°29%
- Thu92°68°39%
- Fri90°70°46%
- Sat84°69°43%
- Sun86°66°43%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 4, 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 — Johnstown
SPC has placed Johnstown in the Slight Risk category for severe thunderstorms today.
- TODAYSLGTSlight Risk
- TOMORROWMRGLMarginal 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 Johnstown
- 15906
- 15905
- 15902
- 15901
- 15907