Hourly Weather | Today Wednesday, March 18, 2026
Waltham, Massachusetts
8 PM
Cloudy Night
34°
Feels Like 28°
0
Humidity: 49%
UV Index: 0
Wind: 7 mph
9 PM
Cloudy Night
32°
Feels Like 27°
0
Humidity: 54%
UV Index: 0
Wind: 7 mph
10 PM
Cloudy Night
30°
Feels Like 27°
0
Humidity: 57%
UV Index: 0
Wind: 6 mph
11 PM
Cloudy Night
30°
Feels Like 27°
0
Humidity: 59%
UV Index: 0
Wind: 6 mph

Hourly Air Quality Forecast - AQI (US EPA)

8 PM
47 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.09 µg/m³
  • PM10: 2.55 µg/m³
  • O3: 0.051 ppm
  • NO2: 2.4 ppb
  • SO2: 0.3 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

9 PM
46 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.25 µg/m³
  • PM10: 2.78 µg/m³
  • O3: 0.049 ppm
  • NO2: 2.5 ppb
  • SO2: 0.3 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

10 PM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.41 µg/m³
  • PM10: 3.04 µg/m³
  • O3: 0.048 ppm
  • NO2: 2.7 ppb
  • SO2: 0.3 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

11 PM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.6 µg/m³
  • PM10: 3.33 µg/m³
  • O3: 0.047 ppm
  • NO2: 2.8 ppb
  • SO2: 0.3 ppb
  • CO: 0.16 ppm

Health Recommendations:

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