Hourly Weather | Today Monday, September 21, 2026
Gaithersburg, Maryland
3 PM
Rainy Weather
73°
Feels Like 70°
66
Humidity: 72%
UV Index: 1
Wind: 6 mph
4 PM
Cloudy Weather
72°
Feels Like 72°
49
Humidity: 77%
UV Index: 1
Wind: 6 mph
5 PM
Cloudy Weather
70°
Feels Like 70°
49
Humidity: 82%
UV Index: 0
Wind: 7 mph
6 PM
Cloudy Weather
68°
Feels Like 66°
49
Humidity: 87%
UV Index: 0
Wind: 6 mph
7 PM
Rainy Weather
66°
Feels Like 63°
56
Humidity: 87%
UV Index: 0
Wind: 6 mph
8 PM
Cloudy Weather
66°
Feels Like 64°
49
Humidity: 87%
UV Index: 0
Wind: 6 mph
9 PM
Cloudy Weather
64°
Feels Like 64°
49
Humidity: 92%
UV Index: 0
Wind: 6 mph
10 PM
Rainy Weather
64°
Feels Like 61°
55
Humidity: 94%
UV Index: 0
Wind: 6 mph
11 PM
Rainy Weather
64°
Feels Like 61°
66
Humidity: 94%
UV Index: 0
Wind: 6 mph

Hourly Air Quality Forecast - AQI (US EPA)

3 PM
24 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.57 µg/m³
  • PM10: 5.3 µg/m³
  • O3: 0.026 ppm
  • NO2: 3 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

4 PM
25 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.02 µg/m³
  • PM10: 5.8 µg/m³
  • O3: 0.027 ppm
  • NO2: 3.1 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

5 PM
25 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.62 µg/m³
  • PM10: 6.43 µg/m³
  • O3: 0.027 ppm
  • NO2: 3.2 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

6 PM
26 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 6.31 µg/m³
  • PM10: 7.11 µg/m³
  • O3: 0.028 ppm
  • NO2: 3.4 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

7 PM
28 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 6.76 µg/m³
  • PM10: 7.52 µg/m³
  • O3: 0.029 ppm
  • NO2: 3.4 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

8 PM
29 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 7.01 µg/m³
  • PM10: 7.76 µg/m³
  • O3: 0.029 ppm
  • NO2: 3.3 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

9 PM
29 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 7.06 µg/m³
  • PM10: 7.73 µg/m³
  • O3: 0.029 ppm
  • NO2: 3.1 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

10 PM
30 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 7.15 µg/m³
  • PM10: 7.76 µg/m³
  • O3: 0.029 ppm
  • NO2: 2.9 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

11 PM
30 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 7.12 µg/m³
  • PM10: 7.74 µg/m³
  • O3: 0.028 ppm
  • NO2: 2.8 ppb
  • SO2: 0.6 ppb
  • CO: 0.19 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.