Ontario, Wisconsin Weather
Prairie lightning bugs rise. Day 77 of spring. Read this microseason across nine climate regions →
Ontario weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Light Rain51%0.07″85°54°—
- FridayJun 5Light Drizzle64%—82°67°-3°
- SaturdayJun 6Overcast20%—82°62°0°
- SundayJun 7Drizzle13%—79°64°-3°
- MondayJun 8Light Showers62%0.46″69°62°-10°
- TuesdayJun 9Light Rain41%0.20″75°66°+6°
- WednesdayJun 10Thunderstorm16%—85°65°+10°
Ozone at AQI 60 — peak already passed at 1 PM under clear skies. AQI up 9 over the last 6 hours (gradual rise). 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 60 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 60
- UV peak
- 4.6 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 60
PM × Wind × Precip
PM2.5 at 9.0 µg/m³, PM10 at 10.8 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.83
- Wind
- breezy
- Recent rain
- 0h 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 4:45 AM
- Moonset
- 1:52 PM
- In sign
- ♒︎ Aquarius
Prairie lightning bugs rise
Ontario at a glance
- Today vs. normal: 14°F above the seasonal normal for this latitude
- Last frost: May 8 (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 — Ontario
SPC has placed Ontario in the Marginal Risk category for severe thunderstorms tomorrow.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWMRGLMarginal Risk
- DAY 3NONENo severe risk
Isolated severe storms possible. Limited threat for hail or damaging wind.
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.