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Hourly Weather | Today › Tuesday, April 28, 2026
Active Weather Warnings
Janesville, Wisconsin
5 AM
Cloudy Weather
48°
Feels Like 39°
7
Humidity: 85%
UV Index: 0
Wind: 13 mph
6 AM
Cloudy Weather
48°
Feels Like 39°
7
Humidity: 82%
UV Index: 0
Wind: 14 mph
7 AM
Cloudy Weather
48°
Feels Like 41°
5
Humidity: 80%
UV Index: 0
Wind: 14 mph
8 AM
Cloudy Weather
48°
Feels Like 39°
0
Humidity: 83%
UV Index: 0
Wind: 15 mph
9 AM
Cloudy Weather
50°
Feels Like 43°
0
Humidity: 75%
UV Index: 1
Wind: 15 mph
10 AM
Cloudy Weather
52°
Feels Like 45°
0
Humidity: 68%
UV Index: 1
Wind: 15 mph
11 AM
Cloudy Weather
54°
Feels Like 50°
0
Humidity: 61%
UV Index: 3
Wind: 14 mph
12 PM
Cloudy Weather
57°
Feels Like 57°
0
Humidity: 53%
UV Index: 5
Wind: 14 mph
1 PM
Cloudy Weather
61°
Feels Like 63°
0
Humidity: 47%
UV Index: 7
Wind: 14 mph
2 PM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 42%
UV Index: 6
Wind: 13 mph
3 PM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 39%
UV Index: 4
Wind: 13 mph
4 PM
Cloudy Weather
64°
Feels Like 63°
0
Humidity: 37%
UV Index: 2
Wind: 13 mph
5 PM
Cloudy Weather
66°
Feels Like 64°
0
Humidity: 33%
UV Index: 1
Wind: 12 mph
6 PM
Cloudy Weather
64°
Feels Like 61°
0
Humidity: 34%
UV Index: 1
Wind: 10 mph
7 PM
Cloudy Weather
63°
Feels Like 59°
1
Humidity: 34%
UV Index: 0
Wind: 9 mph
8 PM
Cloudy Weather
59°
Feels Like 55°
4
Humidity: 39%
UV Index: 0
Wind: 7 mph
9 PM
Cloudy Weather
55°
Feels Like 54°
4
Humidity: 44%
UV Index: 0
Wind: 6 mph
10 PM
Cloudy Weather
54°
Feels Like 52°
4
Humidity: 49%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Weather
52°
Feels Like 52°
5
Humidity: 51%
UV Index: 0
Wind: 5 mph

Hourly Air Quality Forecast - AQI (US EPA)

5 AM
37 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.19 µg/m³
  • PM10: 1.36 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.6 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

6 AM
37 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.18 µg/m³
  • PM10: 1.34 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.6 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

7 AM
37 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.17 µg/m³
  • PM10: 1.34 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.7 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

8 AM
36 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.03 µg/m³
  • PM10: 1.19 µg/m³
  • O3: 0.039 ppm
  • NO2: 0.8 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

9 AM
37 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.9 µg/m³
  • PM10: 1.07 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.8 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

10 AM
38 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.82 µg/m³
  • PM10: 0.99 µg/m³
  • O3: 0.041 ppm
  • NO2: 0.6 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

11 AM
40 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.85 µg/m³
  • PM10: 1.01 µg/m³
  • O3: 0.043 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

12 PM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.91 µg/m³
  • PM10: 1.06 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

1 PM
45 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1 µg/m³
  • PM10: 1.14 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

2 PM
48 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.09 µg/m³
  • PM10: 1.22 µg/m³
  • O3: 0.052 ppm
  • NO2: 0.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

3 PM
50 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.12 µg/m³
  • PM10: 1.25 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

4 PM
51 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.11 µg/m³
  • PM10: 1.23 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

5 PM
53 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.09 µg/m³
  • PM10: 1.22 µg/m³
  • O3: 0.055 ppm
  • NO2: 0.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

6 PM
50 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.11 µg/m³
  • PM10: 1.25 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.7 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

7 PM
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.11 µg/m³
  • PM10: 1.29 µg/m³
  • O3: 0.053 ppm
  • NO2: 0.9 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

8 PM
47 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.15 µg/m³
  • PM10: 1.34 µg/m³
  • O3: 0.051 ppm
  • NO2: 1.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

9 PM
45 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.23 µg/m³
  • PM10: 1.45 µg/m³
  • O3: 0.049 ppm
  • NO2: 1.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

10 PM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.32 µg/m³
  • PM10: 1.56 µg/m³
  • O3: 0.047 ppm
  • NO2: 1.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

11 PM
41 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.38 µg/m³
  • PM10: 1.63 µg/m³
  • O3: 0.045 ppm
  • NO2: 1.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Current Real-Time Air Quality Report

Weather Alerts and Warnings for Janesville

Severe Immediate Observed

Flood Warning

Flood Warning issued April 27 at 9:38PM CDT by NWS Milwaukee/Sullivan WI
Apr 27, 9:38 PM → Apr 28, 9:45 AM
...The Flood Warning continues for the following rivers in
Wisconsin...Illinois...

Rock River At Fort Atkinson affecting Jefferson County.

Fox River Lower Near New Munster affecting Lake and Kenosha
Counties.

Rock River At Newville affecting Rock County.

Rock River Near Lake Koshkonong affecting Jefferson and Rock
Counties.

Rock River At Afton affecting Winnebago and Rock Counties.

Rock River At Jefferson affecting Jefferson County.

ROCK RIVER near LEBANON-3 E-HWY MM BRIDGE affecting Dodge County.

WHAT: Minor flooding is occurring and minor flooding is forecast.

WHERE: Rock River at Afton.

WHEN: Until further notice.

IMPACTS: At 10.5 feet, Floodwaters affect Riverside Park on the
north side of Janesville and South River Road on the south side of
Janesville. Floodwaters affect low spots on South River Rd on the
south side of Janesville. Floodwaters affect a home on South
Christian Rd on the east side of the river in the Afton area.
There is extensive lowland and agricultural land flooding in the
Afton and Janesville areas.

ADDITIONAL DETAILS:
- At 9:00 PM CDT Monday the stage was 10.6 feet.
- Bankfull stage is 8.0 feet.
- Recent Activity...The maximum river stage in the 24 hours
ending at 9:00 PM CDT Monday was 10.7 feet.
- Forecast...The river is expected to rise to a crest of 10.6
feet just after midnight tonight.
- Flood stage is 9.0 feet.
- Flood History...This crest compares to a previous crest of
10.6 feet on 04/12/1923.
- http://www.weather.gov/safety/flood
+ Read More
Caution is urged when walking near riverbanks. Motorists should not attempt to drive around barricades or drive cars through flooded areas. Additional information is available at www.weather.gov. The next statement will be issued Tuesday morning at 945 AM CDT.
Updated: Apr 28, 3:21 AM Source: NWS Alert

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