Janesville, Iowa Weather
Prairie lightning bugs rise. Day 77 of spring. Read this microseason across nine climate regions →
Janesville weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Heavy Showers49%1.3″85°61°—
- FridayJun 5Thunderstorm62%0.26″79°67°-6°
- SaturdayJun 6Drizzle41%—85°63°+6°
- SundayJun 7Light Showers36%—82°66°-3°
- MondayJun 8Showers56%—80°69°-2°
- TuesdayJun 9Light Drizzle35%—88°68°+8°
- WednesdayJun 10Thunderstorm14%—95°72°+7°
AQI 29 (Good), driven by Ozone. AQI down 30 over the last 6 hours — air quality is improving sharply.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 8 AM.
What's driving it
PM × Wind × Precip
PM2.5 at 4.9 µg/m³ (AQI 27) with a 0.89 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.89
- Wind
- light
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 4:48 AM
- Moonset
- 2:04 PM
- In sign
- ♑︎ Capricorn
Prairie lightning bugs rise
Janesville at a glance
- Today vs. normal: 8°F below the seasonal normal for this latitude
- Last frost: May 2 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 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 — Janesville
SPC has placed Janesville in the Slight Risk category for severe thunderstorms tomorrow.
- TODAYMRGLMarginal Risk
- TOMORROWSLGTSlight Risk
- DAY 3SLGTSlight Risk
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.