Janesville, Iowa Weather
Prairie lightning bugs rise. Day 76 of spring. Read this microseason across nine climate regions →
Janesville weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Partly Cloudy——83°58°—
- ThursdayJun 4Light Rain43%0.20″85°60°+2°
- FridayJun 5Thunderstorm88%0.93″79°65°-6°
- SaturdayJun 6Light Showers56%—83°65°+4°
- SundayJun 7Light Drizzle28%—81°64°-2°
- MondayJun 8Light Showers53%—74°65°-7°
- TuesdayJun 9Light Drizzle28%—81°68°+7°
Ozone at AQI 75 — peak already passed at 1 PM under clear skies. AQI up 19 in the last 6 hours — air quality is degrading. Levels should ease through evening.
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 75 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 75
- UV peak
- 2.5 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 75
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).
The higher the clouds, the finer the weather.
- Moonrise
- 4:12 AM
- Moonset
- 12:59 PM
- In sign
- ♑︎ Capricorn
Prairie lightning bugs rise
Janesville at a glance
- Today vs. normal: 11°F above 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 3, 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 day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWMRGLMarginal 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.