Hourly Weather | Today Monday, September 21, 2026
South Portland, Maine
12 PM
Cloudy Weather
63°
Feels Like 66°
0
Humidity: 62%
UV Index: 4
Wind: 9 mph
1 PM
Cloudy Weather
64°
Feels Like 68°
0
Humidity: 58%
UV Index: 5
Wind: 8 mph
2 PM
Cloudy Weather
64°
Feels Like 68°
0
Humidity: 56%
UV Index: 4
Wind: 8 mph
3 PM
Cloudy Weather
66°
Feels Like 68°
0
Humidity: 54%
UV Index: 4
Wind: 8 mph
4 PM
Cloudy Weather
64°
Feels Like 66°
0
Humidity: 57%
UV Index: 3
Wind: 8 mph
5 PM
Cloudy Weather
64°
Feels Like 64°
0
Humidity: 58%
UV Index: 2
Wind: 8 mph
6 PM
Cloudy Weather
63°
Feels Like 63°
0
Humidity: 59%
UV Index: 1
Wind: 8 mph
7 PM
Cloudy Night
61°
Feels Like 59°
0
Humidity: 63%
UV Index: 0
Wind: 8 mph
8 PM
Cloudy Night
59°
Feels Like 55°
0
Humidity: 68%
UV Index: 0
Wind: 8 mph
9 PM
Cloudy Night
57°
Feels Like 54°
0
Humidity: 70%
UV Index: 0
Wind: 8 mph
10 PM
Cloudy Night
55°
Feels Like 52°
0
Humidity: 70%
UV Index: 0
Wind: 8 mph
11 PM
Cloudy Night
55°
Feels Like 50°
0
Humidity: 71%
UV Index: 0
Wind: 9 mph

Hourly Air Quality Forecast - AQI (US EPA)

12 PM
33 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.91 µg/m³
  • PM10: 2.43 µg/m³
  • O3: 0.036 ppm
  • NO2: 1.3 ppb
  • SO2: 0.3 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.24 µg/m³
  • PM10: 2.66 µg/m³
  • O3: 0.040 ppm
  • NO2: 1.1 ppb
  • SO2: 0.3 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.43 µg/m³
  • PM10: 2.81 µg/m³
  • O3: 0.041 ppm
  • NO2: 1 ppb
  • SO2: 0.3 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.58 µg/m³
  • PM10: 2.97 µg/m³
  • O3: 0.042 ppm
  • NO2: 1.1 ppb
  • SO2: 0.3 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 2.82 µg/m³
  • PM10: 3.27 µg/m³
  • O3: 0.041 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.

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

Pollutant Concentrations:

  • PM2.5: 2.97 µg/m³
  • PM10: 3.47 µg/m³
  • O3: 0.039 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.

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

Pollutant Concentrations:

  • PM2.5: 3.24 µg/m³
  • PM10: 3.95 µg/m³
  • O3: 0.033 ppm
  • NO2: 4.5 ppb
  • SO2: 0.4 ppb
  • CO: 0.19 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.65 µg/m³
  • PM10: 4.79 µg/m³
  • O3: 0.026 ppm
  • NO2: 7.2 ppb
  • SO2: 0.4 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: 4.02 µg/m³
  • PM10: 5.58 µg/m³
  • O3: 0.022 ppm
  • NO2: 8.4 ppb
  • SO2: 0.4 ppb
  • CO: 0.22 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.21 µg/m³
  • PM10: 6.02 µg/m³
  • O3: 0.021 ppm
  • NO2: 8.4 ppb
  • SO2: 0.4 ppb
  • CO: 0.22 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.2 µg/m³
  • PM10: 6.02 µg/m³
  • O3: 0.020 ppm
  • NO2: 7.6 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
17 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 3.88 µg/m³
  • PM10: 5.45 µg/m³
  • O3: 0.018 ppm
  • NO2: 6.6 ppb
  • SO2: 0.4 ppb
  • CO: 0.21 ppm

Health Recommendations:

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