Today | Weather | Wednesday, March 18, 2026

Weather in Watertown, South Dakota

04:00 AM
Now
Cloudy Night
21° F
Feels Like 14°
Precipitation 0 %
Wind 8 mph
Humidity 93 %
Today
Cloudy Weather
Day 45°
Night 30°
Precipitation 1 %
Wind 9 mph
UV Index (0 - 11+) 4
Overnight Frost 12 AM – 9 AM
Tomorrow Morning Frost 3 AM – 7 AM

Watertown Weather Forecast Updated

Last updated on

Air Quality in Watertown

NOW
35 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 1 µg/m³
PM10 1.6 µg/m³
O3 0.038 ppm
NO2 1 ppb
SO2 0 ppb
CO 0.12 ppm
NH3 0.74 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)
PM2.51 µg/m³
PM101.6 µg/m³
O374.47 µg/m³
NO21.79 µg/m³
SO20.02 µg/m³
CO137.43 µg/m³
NH30.74 µg/m³
NO0 µg/m³