Today | Weather | Monday, September 21, 2026

Weather in Norwalk, Connecticut

01:54 PM
Now
Cloudy Weather
66° F
Feels Like 68°
Precipitation 7 %
Wind 10 mph
UV Index (0 - 11+) 4
Humidity 63 %
Today
Cloudy Weather
Day 72°
Night 55°
Precipitation 25 %
Wind 10 mph
UV Index (0 - 11+) 5

Norwalk Weather Forecast Updated

6 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 21, 2025)
Cloudy Night

Day

70°

Night

48°

Wind

5 mph

Precipitation

0 %

Air Quality in Norwalk

NOW
33 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 4.19 µg/m³
PM10 6.66 µg/m³
O3 0.036 ppm
NO2 4.6 ppb
SO2 1.1 ppb
CO 0.19 ppm
NH3 0.31 µg/m³
NO 1.07 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)
PM2.54.19 µg/m³
PM106.66 µg/m³
O370.66 µg/m³
NO28.59 µg/m³
SO22.85 µg/m³
CO222.63 µg/m³
NH30.31 µg/m³
NO1.07 µg/m³