Today | Weather | Monday, September 21, 2026

Weather in Frederick, Maryland

01:52 PM
Now
Rainy Weather
68° F
Feels Like 64°
Precipitation 52 %
Wind 7 mph
UV Index (0 - 11+) 1
Humidity 74 %
Today
Rainy Weather
Day 70°
Night 57°
Precipitation 87 %
Wind 7 mph
UV Index (0 - 11+) 1

Frederick Weather Forecast Updated

16 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 21, 2025)
Rainy Weather

Day

72°

Night

59°

Wind

4 mph

UV Index

10

Precipitation

49 %

Air Quality in Frederick

NOW
20 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 3.39 µg/m³
PM10 4.13 µg/m³
O3 0.022 ppm
NO2 3.1 ppb
SO2 0.4 ppb
CO 0.18 ppm
NH3 0.58 µg/m³
NO 0.64 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)
PM2.53.39 µg/m³
PM104.13 µg/m³
O342.22 µg/m³
NO25.8 µg/m³
SO21.16 µg/m³
CO208.87 µg/m³
NH30.58 µg/m³
NO0.64 µg/m³