Ontario, Wisconsin Weather
Cicadas claim the afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Ontario weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Foggy22%—82°66°—
- SundayJul 5Overcast12%—81°66°-1°
- MondayJul 6Clear——80°62°-1°
- TuesdayJul 7Overcast——82°63°+2°
- WednesdayJul 8T-storm w/ Hail49%0.01″79°65°-3°
- ThursdayJul 9Light Drizzle52%—77°64°-2°
- FridayJul 10Overcast11%—78°60°+1°
AQI 33 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±4 points). PM2.5 at 8.8 µg/m³ (AQI 49) with a 0.82 fine-to-coarse ratio and 6 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 39. Overcast through the UV peak window (cloud cover ~62%) — afternoon ozone should stay flat.
- Present
- AQI 39
- UV peak
- 6.9 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 18
PM × Wind × Precip
PM2.5 at 8.8 µg/m³ (AQI 49) with a 0.82 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.82
- 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).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:02 PM
- Moonset
- 10:04 AM
- In sign
- ♓︎ Pisces
Cicadas claim the afternoon
Ontario at a glance
- Today vs. normal: 13°F above the seasonal normal for this latitude
- Last frost: May 8 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 54651
16-Day Forecast — Ontario
- Sat82°66°22%
- Sun81°66°12%
- Mon80°62°4%
- Tue82°63°3%
- Wed79°65°49%
- Thu77°64°52%
- Fri78°60°11%
- Sat80°62°9%
- Sun72°57°10%
- Mon76°53°7%
- Tue78°61°6%
- Wed78°62°19%
- Thu77°69°19%
- Fri82°67°20%
- Sat84°69°26%
- Sun84°70°35%
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 — Ontario
SPC includes Ontario in the general thunderstorm area today — no severe risk, but storms are possible.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3NONENo severe risk
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 Ontario
- 54651