Today | Weather | Wednesday, March 18, 2026

Weather in St. Peters, Missouri

04:14 AM
Now
Snowy Weather
34° F
Feels Like 25°
Precipitation 51 %
Wind 9 mph
Humidity 58 %
Today
Cloudy Weather
Day 64°
Night 41°
Precipitation 3 %
Wind 11 mph
UV Index (0 - 11+) 5

St. Peters Weather Forecast Updated

28 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (March 18, 2025)

Day

84°

Night

54°

Air Quality in St. Peters

NOW
47 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 3.04 µg/m³
PM10 3.88 µg/m³
O3 0.050 ppm
NO2 0.6 ppb
SO2 0.4 ppb
CO 0.13 ppm
NH3 1.9 µg/m³
NO 0 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

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

Show raw pollutant concentrations (µg/m³)
PM2.53.04 µg/m³
PM103.88 µg/m³
O399.05 µg/m³
NO21.17 µg/m³
SO21.17 µg/m³
CO150.09 µg/m³
NH31.9 µg/m³
NO0 µg/m³