Today | Weather | Wednesday, May 20, 2026

Weather in St. Peters, Missouri

04:52 PM
Now
Cloudy Weather
68° F
Feels Like 68°
Precipitation 20 %
Wind 8 mph
UV Index (0 - 11+) 2
Humidity 61 %
Today
Rainy Weather
Day 68°
Night 55°
Precipitation 55 %
Wind 8 mph
UV Index (0 - 11+) 4

St. Peters Weather Forecast Updated

11 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (May 20, 2025)

Day

81°

Night

57°

Air Quality in St. Peters

NOW
33 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 3.6 µg/m³
PM10 3.9 µg/m³
O3 0.036 ppm
NO2 0.6 ppb
SO2 0.7 ppb
CO 0.11 ppm
NH3 1.24 µg/m³
NO 0.14 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)
PM2.53.6 µg/m³
PM103.9 µg/m³
O369.95 µg/m³
NO21.04 µg/m³
SO21.89 µg/m³
CO124.11 µg/m³
NH31.24 µg/m³
NO0.14 µg/m³