Today | Weather | Wednesday, September 9, 2026

Weather in St. Peters, Missouri

07:53 PM
Now
Stormy Weather
82° F
Feels Like 86°
Precipitation 51 %
Wind 6 mph
Humidity 74 %
Today
Sunny with a Chance of Thunderstorms
Day 95°
Night 73°
Precipitation 90 %
Wind 7 mph
UV Index (0 - 11+) 6

St. Peters Weather Forecast Updated

Weather Forecast History
Last Year's Weather on This Day (September 9, 2025)

Day

82°

Night

46°

Air Quality in St. Peters

NOW
27 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 5.21 µg/m³
PM10 5.44 µg/m³
O3 0.029 ppm
NO2 0.9 ppb
SO2 0.2 ppb
CO 0.10 ppm
NH3 0.37 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)
PM2.55.21 µg/m³
PM105.44 µg/m³
O356.77 µg/m³
NO21.69 µg/m³
SO20.53 µg/m³
CO118.66 µg/m³
NH30.37 µg/m³
NO0 µg/m³