Hourly Weather | Today Monday, September 21, 2026
Somerville, Massachusetts
2 PM
Cloudy Weather
68°
Feels Like 70°
0
Humidity: 48%
UV Index: 4
Wind: 10 mph
3 PM
Cloudy Weather
66°
Feels Like 68°
0
Humidity: 50%
UV Index: 3
Wind: 10 mph
4 PM
Cloudy Weather
66°
Feels Like 66°
0
Humidity: 55%
UV Index: 2
Wind: 9 mph
5 PM
Cloudy Weather
64°
Feels Like 64°
0
Humidity: 57%
UV Index: 2
Wind: 8 mph
6 PM
Cloudy Weather
63°
Feels Like 63°
0
Humidity: 62%
UV Index: 1
Wind: 7 mph
7 PM
Cloudy Night
61°
Feels Like 59°
0
Humidity: 69%
UV Index: 0
Wind: 6 mph
8 PM
Cloudy Night
57°
Feels Like 57°
0
Humidity: 80%
UV Index: 0
Wind: 5 mph
9 PM
Cloudy Night
55°
Feels Like 55°
0
Humidity: 87%
UV Index: 0
Wind: 5 mph
10 PM
Cloudy Night
54°
Feels Like 52°
0
Humidity: 94%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
55°
Feels Like 54°
0
Humidity: 88%
UV Index: 0
Wind: 6 mph

Hourly Air Quality Forecast - AQI (US EPA)

2 PM
41 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.7 µg/m³
  • PM10: 4.36 µg/m³
  • O3: 0.044 ppm
  • NO2: 1.1 ppb
  • SO2: 0.4 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.22 µg/m³
  • PM10: 4.83 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.9 ppb
  • SO2: 0.4 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.42 µg/m³
  • PM10: 4.94 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.9 ppb
  • SO2: 0.4 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.41 µg/m³
  • PM10: 4.87 µg/m³
  • O3: 0.048 ppm
  • NO2: 1 ppb
  • SO2: 0.4 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.25 µg/m³
  • PM10: 4.66 µg/m³
  • O3: 0.047 ppm
  • NO2: 1.5 ppb
  • SO2: 0.4 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.1 µg/m³
  • PM10: 4.52 µg/m³
  • O3: 0.044 ppm
  • NO2: 2.1 ppb
  • SO2: 0.4 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.86 µg/m³
  • PM10: 4.3 µg/m³
  • O3: 0.042 ppm
  • NO2: 2.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.18 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.53 µg/m³
  • PM10: 3.95 µg/m³
  • O3: 0.040 ppm
  • NO2: 2.2 ppb
  • SO2: 0.4 ppb
  • CO: 0.18 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.31 µg/m³
  • PM10: 3.72 µg/m³
  • O3: 0.039 ppm
  • NO2: 2.1 ppb
  • SO2: 0.4 ppb
  • CO: 0.18 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.25 µg/m³
  • PM10: 3.69 µg/m³
  • O3: 0.037 ppm
  • NO2: 1.9 ppb
  • SO2: 0.3 ppb
  • CO: 0.18 ppm

Health Recommendations:

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