Hourly Weather | Today Wednesday, December 24, 2025
Waltham, Massachusetts
3 PM
Snowy Weather
34°
Feels Like 16°
53
Humidity: 62%
Wind: 23 mph
UV Index: 0
4 PM
Cloudy Weather
34°
Feels Like 16°
40
Humidity: 62%
Wind: 22 mph
UV Index: 0
5 PM
Cloudy Weather
34°
Feels Like 18°
34
Humidity: 64%
Wind: 18 mph
UV Index: 0
6 PM
Cloudy Night
30°
Feels Like 18°
22
Humidity: 66%
Wind: 15 mph
UV Index: 0
7 PM
Cloudy Night
30°
Feels Like 19°
0
Humidity: 70%
Wind: 12 mph
UV Index: 0
8 PM
Cloudy Night
28°
Feels Like 21°
0
Humidity: 72%
Wind: 8 mph
UV Index: 0
9 PM
Cloudy Night
27°
Feels Like 27°
0
Humidity: 75%
Wind: 5 mph
UV Index: 0
10 PM
Cloudy Night
27°
Feels Like 27°
0
Humidity: 76%
Wind: 5 mph
UV Index: 0
11 PM
Cloudy Night
27°
Feels Like 27°
0
Humidity: 76%
Wind: 5 mph
UV Index: 0

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 0.63 µg/m³
  • PM10: 1.04 µg/m³
  • O3: 0.025 ppm
  • NO2: 3.2 ppb
  • SO2: 0.2 ppb
  • CO: 0.18 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.73 µg/m³
  • PM10: 1.18 µg/m³
  • O3: 0.024 ppm
  • NO2: 4 ppb
  • SO2: 0.2 ppb
  • CO: 0.19 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.85 µg/m³
  • PM10: 1.34 µg/m³
  • O3: 0.023 ppm
  • NO2: 4.9 ppb
  • SO2: 0.2 ppb
  • CO: 0.19 ppm

Health Recommendations:

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

6 PM
21 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.07 µg/m³
  • PM10: 1.61 µg/m³
  • O3: 0.023 ppm
  • NO2: 5.7 ppb
  • SO2: 0.3 ppb
  • CO: 0.20 ppm

Health Recommendations:

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

7 PM
20 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.51 µg/m³
  • PM10: 2.12 µg/m³
  • O3: 0.022 ppm
  • NO2: 6.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.21 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.96 µg/m³
  • PM10: 2.65 µg/m³
  • O3: 0.022 ppm
  • NO2: 6.5 ppb
  • SO2: 0.3 ppb
  • CO: 0.21 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.48 µg/m³
  • PM10: 3.26 µg/m³
  • O3: 0.021 ppm
  • NO2: 6.8 ppb
  • SO2: 0.4 ppb
  • CO: 0.21 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.92 µg/m³
  • PM10: 3.8 µg/m³
  • O3: 0.021 ppm
  • NO2: 7.1 ppb
  • SO2: 0.4 ppb
  • CO: 0.22 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.33 µg/m³
  • PM10: 4.32 µg/m³
  • O3: 0.020 ppm
  • NO2: 7.4 ppb
  • SO2: 0.4 ppb
  • CO: 0.22 ppm

Health Recommendations:

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