Hourly Weather | Today Tuesday, April 21, 2026
Cambridge, Massachusetts
5 AM
Cloudy Night
34°
Feels Like 27°
40
Humidity: 58%
UV Index: 0
Wind: 8 mph
6 AM
Cloudy Weather
32°
Feels Like 27°
34
Humidity: 60%
UV Index: 0
Wind: 7 mph
7 AM
Cloudy Weather
34°
Feels Like 28°
22
Humidity: 53%
UV Index: 1
Wind: 8 mph
8 AM
Cloudy Weather
36°
Feels Like 34°
0
Humidity: 48%
UV Index: 2
Wind: 8 mph
9 AM
Cloudy Weather
39°
Feels Like 39°
0
Humidity: 42%
UV Index: 3
Wind: 7 mph
10 AM
Cloudy Weather
41°
Feels Like 46°
0
Humidity: 37%
UV Index: 4
Wind: 6 mph
11 AM
Cloudy Weather
43°
Feels Like 52°
0
Humidity: 33%
UV Index: 5
Wind: 6 mph
12 PM
Cloudy Weather
45°
Feels Like 54°
0
Humidity: 31%
UV Index: 7
Wind: 7 mph
1 PM
Cloudy Weather
46°
Feels Like 54°
0
Humidity: 30%
UV Index: 7
Wind: 7 mph
2 PM
Cloudy Weather
46°
Feels Like 54°
0
Humidity: 30%
UV Index: 7
Wind: 8 mph
3 PM
Cloudy Weather
48°
Feels Like 52°
0
Humidity: 30%
UV Index: 5
Wind: 9 mph
4 PM
Cloudy Weather
46°
Feels Like 46°
0
Humidity: 32%
UV Index: 4
Wind: 10 mph
5 PM
Cloudy Weather
46°
Feels Like 43°
0
Humidity: 35%
UV Index: 3
Wind: 12 mph
6 PM
Cloudy Weather
46°
Feels Like 39°
0
Humidity: 39%
UV Index: 2
Wind: 12 mph
7 PM
Cloudy Weather
45°
Feels Like 37°
0
Humidity: 44%
UV Index: 1
Wind: 12 mph
8 PM
Cloudy Night
43°
Feels Like 36°
0
Humidity: 51%
UV Index: 0
Wind: 10 mph
9 PM
Cloudy Night
41°
Feels Like 34°
0
Humidity: 55%
UV Index: 0
Wind: 10 mph
10 PM
Cloudy Night
39°
Feels Like 34°
0
Humidity: 58%
UV Index: 0
Wind: 10 mph
11 PM
Cloudy Weather
39°
Feels Like 32°
0
Humidity: 61%
UV Index: 0
Wind: 9 mph

Hourly Air Quality Forecast - AQI (US EPA)

5 AM
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.61 µg/m³
  • PM10: 1.33 µg/m³
  • O3: 0.052 ppm
  • NO2: 1.5 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

6 AM
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.66 µg/m³
  • PM10: 1.43 µg/m³
  • O3: 0.053 ppm
  • NO2: 1.5 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

7 AM
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.78 µg/m³
  • PM10: 1.6 µg/m³
  • O3: 0.053 ppm
  • NO2: 1.8 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

8 AM
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.9 µg/m³
  • PM10: 1.77 µg/m³
  • O3: 0.053 ppm
  • NO2: 2.2 ppb
  • SO2: 0.5 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

9 AM
50 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.99 µg/m³
  • PM10: 1.88 µg/m³
  • O3: 0.054 ppm
  • NO2: 2.2 ppb
  • SO2: 0.5 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

10 AM
50 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.15 µg/m³
  • PM10: 2.05 µg/m³
  • O3: 0.054 ppm
  • NO2: 2.1 ppb
  • SO2: 0.5 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

11 AM
52 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.52 µg/m³
  • PM10: 2.42 µg/m³
  • O3: 0.055 ppm
  • NO2: 1.9 ppb
  • SO2: 0.5 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

12 PM
58 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.74 µg/m³
  • PM10: 2.54 µg/m³
  • O3: 0.057 ppm
  • NO2: 1.5 ppb
  • SO2: 0.5 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

1 PM
62 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.04 µg/m³
  • PM10: 2.78 µg/m³
  • O3: 0.058 ppm
  • NO2: 1.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

2 PM
66 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.56 µg/m³
  • PM10: 3.29 µg/m³
  • O3: 0.059 ppm
  • NO2: 1.2 ppb
  • SO2: 0.4 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

3 PM
70 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.86 µg/m³
  • PM10: 3.54 µg/m³
  • O3: 0.060 ppm
  • NO2: 1.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

4 PM
72 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.84 µg/m³
  • PM10: 3.46 µg/m³
  • O3: 0.061 ppm
  • NO2: 1.2 ppb
  • SO2: 0.3 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

5 PM
75 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.55 µg/m³
  • PM10: 3.08 µg/m³
  • O3: 0.062 ppm
  • NO2: 1 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

6 PM
80 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.21 µg/m³
  • PM10: 2.69 µg/m³
  • O3: 0.064 ppm
  • NO2: 0.7 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

7 PM
78 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.09 µg/m³
  • PM10: 2.61 µg/m³
  • O3: 0.063 ppm
  • NO2: 1 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

8 PM
76 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.02 µg/m³
  • PM10: 2.63 µg/m³
  • O3: 0.062 ppm
  • NO2: 1 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

9 PM
74 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.94 µg/m³
  • PM10: 2.63 µg/m³
  • O3: 0.062 ppm
  • NO2: 0.9 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

10 PM
72 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.86 µg/m³
  • PM10: 2.6 µg/m³
  • O3: 0.061 ppm
  • NO2: 0.8 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

11 PM
70 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.78 µg/m³
  • PM10: 2.58 µg/m³
  • O3: 0.060 ppm
  • NO2: 0.7 ppb
  • SO2: 0.2 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.