Hourly Weather | Today Wednesday, March 18, 2026
Watertown, South Dakota
6 AM
Cloudy Night
25°
Feels Like 19°
0
Frost Risk: 99%
Humidity: 99%
UV Index: 0
Wind: 7 mph
7 AM
Cloudy Night
27°
Feels Like 21°
0
Frost Risk: 93%
Humidity: 97%
UV Index: 0
Wind: 7 mph
8 AM
Cloudy Weather
27°
Feels Like 25°
0
Frost Risk: 100%
Humidity: 90%
UV Index: 1
Wind: 6 mph
9 AM
Cloudy Weather
30°
Feels Like 28°
0
Frost Risk: 79%
Humidity: 85%
UV Index: 2
Wind: 7 mph
10 AM
Cloudy Weather
34°
Feels Like 34°
0
Humidity: 83%
UV Index: 3
Wind: 7 mph
11 AM
Cloudy Weather
37°
Feels Like 39°
0
Humidity: 82%
UV Index: 3
Wind: 7 mph
12 PM
Cloudy Weather
39°
Feels Like 43°
0
Humidity: 80%
UV Index: 4
Wind: 7 mph
1 PM
Cloudy Weather
41°
Feels Like 45°
0
Humidity: 79%
UV Index: 4
Wind: 7 mph
2 PM
Cloudy Weather
43°
Feels Like 45°
0
Humidity: 76%
UV Index: 3
Wind: 8 mph
3 PM
Cloudy Weather
45°
Feels Like 43°
0
Humidity: 73%
UV Index: 2
Wind: 9 mph
4 PM
Cloudy Weather
46°
Feels Like 43°
0
Humidity: 68%
UV Index: 2
Wind: 9 mph
5 PM
Cloudy Weather
45°
Feels Like 41°
0
Humidity: 74%
UV Index: 1
Wind: 9 mph
6 PM
Cloudy Weather
43°
Feels Like 37°
0
Humidity: 82%
UV Index: 0
Wind: 9 mph
7 PM
Cloudy Weather
41°
Feels Like 36°
0
Humidity: 91%
UV Index: 0
Wind: 9 mph
8 PM
Cloudy Night
39°
Feels Like 34°
0
Humidity: 93%
UV Index: 0
Wind: 8 mph
9 PM
Cloudy Night
39°
Feels Like 34°
0
Humidity: 93%
UV Index: 0
Wind: 7 mph
10 PM
Cloudy Night
37°
Feels Like 34°
0
Humidity: 93%
UV Index: 0
Wind: 6 mph
11 PM
Cloudy Night
36°
Feels Like 34°
0
Humidity: 94%
UV Index: 0
Wind: 6 mph

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 0.83 µg/m³
  • PM10: 1.6 µg/m³
  • O3: 0.038 ppm
  • NO2: 0.8 ppb
  • SO2: 0 ppb
  • CO: 0.11 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.88 µg/m³
  • PM10: 1.69 µg/m³
  • O3: 0.036 ppm
  • NO2: 0.9 ppb
  • SO2: 0 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.94 µg/m³
  • PM10: 1.8 µg/m³
  • O3: 0.035 ppm
  • NO2: 1.3 ppb
  • SO2: 0 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.01 µg/m³
  • PM10: 1.91 µg/m³
  • O3: 0.034 ppm
  • NO2: 1.9 ppb
  • SO2: 0 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.06 µg/m³
  • PM10: 2 µg/m³
  • O3: 0.034 ppm
  • NO2: 1.8 ppb
  • SO2: 0 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.35 µg/m³
  • PM10: 2.31 µg/m³
  • O3: 0.035 ppm
  • NO2: 1.4 ppb
  • SO2: 0 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.34 µg/m³
  • PM10: 3.32 µg/m³
  • O3: 0.036 ppm
  • NO2: 1.2 ppb
  • SO2: 0 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.15 µg/m³
  • PM10: 5.16 µg/m³
  • O3: 0.039 ppm
  • NO2: 1 ppb
  • SO2: 0 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.25 µg/m³
  • PM10: 7.31 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.9 ppb
  • SO2: 0 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 7.69 µg/m³
  • PM10: 8.8 µg/m³
  • O3: 0.051 ppm
  • NO2: 1 ppb
  • SO2: 0 ppb
  • CO: 0.14 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: 8.7 µg/m³
  • PM10: 9.83 µg/m³
  • O3: 0.054 ppm
  • NO2: 1.1 ppb
  • SO2: 0 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 9.22 µg/m³
  • PM10: 10.41 µg/m³
  • O3: 0.056 ppm
  • NO2: 1.6 ppb
  • SO2: 0 ppb
  • CO: 0.15 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 8.18 µg/m³
  • PM10: 9.38 µg/m³
  • O3: 0.053 ppm
  • NO2: 2.6 ppb
  • SO2: 0 ppb
  • CO: 0.15 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 6.42 µg/m³
  • PM10: 7.58 µg/m³
  • O3: 0.047 ppm
  • NO2: 4 ppb
  • SO2: 0 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.78 µg/m³
  • PM10: 4.81 µg/m³
  • O3: 0.038 ppm
  • NO2: 4.6 ppb
  • SO2: 0 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.1 µg/m³
  • PM10: 3 µg/m³
  • O3: 0.033 ppm
  • NO2: 4.4 ppb
  • SO2: 0 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.72 µg/m³
  • PM10: 2.51 µg/m³
  • O3: 0.030 ppm
  • NO2: 4 ppb
  • SO2: 0 ppb
  • CO: 0.15 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.45 µg/m³
  • PM10: 2.15 µg/m³
  • O3: 0.030 ppm
  • NO2: 3.4 ppb
  • SO2: 0 ppb
  • CO: 0.15 ppm

Health Recommendations:

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