Hourly Weather | Today Wednesday, March 18, 2026
St. Peters, Missouri
6 AM
Cloudy Night
36°
Feels Like 28°
47
Humidity: 63%
UV Index: 0
Wind: 8 mph
7 AM
Cloudy Weather
36°
Feels Like 30°
27
Humidity: 68%
UV Index: 0
Wind: 7 mph
8 AM
Cloudy Weather
34°
Feels Like 21°
0
Humidity: 69%
UV Index: 1
Wind: 15 mph
9 AM
Cloudy Weather
37°
Feels Like 27°
0
Humidity: 67%
UV Index: 2
Wind: 15 mph
10 AM
Sunny Weather
43°
Feels Like 37°
0
Humidity: 57%
UV Index: 3
Wind: 14 mph
11 AM
Sunny Weather
48°
Feels Like 45°
0
Humidity: 51%
UV Index: 4
Wind: 14 mph
12 PM
Sunny Weather
54°
Feels Like 52°
0
Humidity: 46%
UV Index: 5
Wind: 14 mph
1 PM
Sunny Weather
57°
Feels Like 55°
0
Humidity: 44%
UV Index: 5
Wind: 14 mph
2 PM
Sunny Weather
59°
Feels Like 63°
0
Humidity: 41%
UV Index: 5
Wind: 9 mph
3 PM
Sunny Weather
63°
Feels Like 64°
0
Humidity: 39%
UV Index: 4
Wind: 9 mph
4 PM
Cloudy Weather
64°
Feels Like 66°
0
Humidity: 39%
UV Index: 3
Wind: 9 mph
5 PM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 42%
UV Index: 2
Wind: 8 mph
6 PM
Cloudy Weather
61°
Feels Like 61°
0
Humidity: 48%
UV Index: 1
Wind: 6 mph
7 PM
Cloudy Weather
57°
Feels Like 57°
0
Humidity: 55%
UV Index: 0
Wind: 4 mph
8 PM
Cloudy Night
55°
Feels Like 55°
0
Humidity: 61%
UV Index: 0
Wind: 4 mph
9 PM
Cloudy Night
52°
Feels Like 52°
0
Humidity: 68%
UV Index: 0
Wind: 4 mph
10 PM
Cloudy Night
50°
Feels Like 48°
0
Humidity: 74%
UV Index: 0
Wind: 4 mph
11 PM
Cloudy Night
46°
Feels Like 45°
0
Humidity: 81%
UV Index: 0
Wind: 4 mph

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 3.3 µg/m³
  • PM10: 4.11 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.6 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.5 µg/m³
  • PM10: 4.26 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.6 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.71 µg/m³
  • PM10: 4.52 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.7 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.85 µg/m³
  • PM10: 4.84 µg/m³
  • O3: 0.046 ppm
  • NO2: 1 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.26 µg/m³
  • PM10: 5.48 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.9 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.93 µg/m³
  • PM10: 6.39 µg/m³
  • O3: 0.050 ppm
  • NO2: 0.7 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.08 µg/m³
  • PM10: 6.63 µg/m³
  • O3: 0.052 ppm
  • NO2: 0.6 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.69 µg/m³
  • PM10: 6.27 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.5 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

2 PM
59 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.4 µg/m³
  • PM10: 6.01 µg/m³
  • O3: 0.057 ppm
  • NO2: 0.4 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

3 PM
62 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.35 µg/m³
  • PM10: 5.9 µg/m³
  • O3: 0.058 ppm
  • NO2: 0.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.21 µg/m³
  • PM10: 5.64 µg/m³
  • O3: 0.058 ppm
  • NO2: 0.3 ppb
  • SO2: 0.4 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
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.3 µg/m³
  • PM10: 5.59 µg/m³
  • O3: 0.053 ppm
  • NO2: 0.6 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.54 µg/m³
  • PM10: 5.75 µg/m³
  • O3: 0.047 ppm
  • NO2: 1.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.72 µg/m³
  • PM10: 5.92 µg/m³
  • O3: 0.042 ppm
  • NO2: 2.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.9 µg/m³
  • PM10: 6.12 µg/m³
  • O3: 0.038 ppm
  • NO2: 3.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.13 µg/m³
  • PM10: 6.37 µg/m³
  • O3: 0.035 ppm
  • NO2: 3.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.34 µg/m³
  • PM10: 6.6 µg/m³
  • O3: 0.032 ppm
  • NO2: 3.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.18 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.44 µg/m³
  • PM10: 6.72 µg/m³
  • O3: 0.031 ppm
  • NO2: 3 ppb
  • SO2: 0.1 ppb
  • CO: 0.17 ppm

Health Recommendations:

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