Today | Weather | Wednesday, March 18, 2026

Weather in South Portland, Maine

05:46 AM
Now
Cloudy Night
19° F
Feels Like
Precipitation 0 %
Wind 14 mph
Humidity 54 %
Today
Cloudy Weather
Day 32°
Night 27°
Precipitation 0 %
Wind 12 mph
UV Index (0 - 11+) 4
Overnight Frost 4 AM – 7 AM

South Portland Weather Forecast Updated

15 minutes ago
Last updated on

Air Quality in South Portland

NOW
47 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 0.5 µg/m³
PM10 0.85 µg/m³
O3 0.051 ppm
NO2 1.6 ppb
SO2 0.4 ppb
CO 0.14 ppm
NH3 0.23 µg/m³
NO 0 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

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

Show raw pollutant concentrations (µg/m³)
PM2.50.5 µg/m³
PM100.85 µg/m³
O399.44 µg/m³
NO23.05 µg/m³
SO20.93 µg/m³
CO165.2 µg/m³
NH30.23 µg/m³
NO0 µg/m³