Air Quality in St. Thomas, Canada
Windy
28.4°C · 56.3% humidity
28.4°
Feels 31.6°
114
Unhealthy for sensitive groups
Sensitive groups should reduce prolonged outdoor exertion.
Model forecast
Nearby Monitoring Stations
St. Thomas's air quality — share it
AQI Forecast
Calibrated
58
10am
58
58
114
1pm
98
87
79
4pm
73
67
64
7pm
61
60
59
10pm
58
57
57
1am
57
57
56
4am
56
58
58
7am
65
55
Station readings
18h ago
AQI 105
PM2.5 37.3 µg/m³ · 18h ago
CAMS model
adj +31
27
27
27
27
27
27
27
27
25
25
25
25
25
25
25
25
25
25
25
25
27
27
34
24
Air Quality Index Trend
8h · 2 stnSt. Thomas's air quality is primarily affected by vehicle emissions and industrial activity. Seasonal wildfire smoke and weather patterns can cause periodic air quality deterioration. Current PM2.5 concentration in St. Thomas is 2.7× the WHO 24-hour guideline of 15 µg/m³.
56.3%
Humidity
45.5 km/h
Wind SSE
1013.6 hPa
Pressure
14.9
UV Extreme
GoodModerateUSGUnhealthyVery UnhealthyHazardous
Which pollutant is driving the AQI?
PM2.5▲
40.72 µg/m³
PM10
84.3 µg/m³
050100150200300500
What is the weather forecast for St. Thomas?
Temperature & Precipitation
PM2.5 Trend
8h · 2 stationsPM2.540.72 µg/m³
×2.7 WHO
Unhealthy for sensitive groups
PM1084.3 µg/m³
Moderate
UV INDEX14.9
Extreme
What is the 7-day forecast for St. Thomas?
07-21
28.4° 21.0°
6.62 mm
07-22
26.5° 19.0°
3.31 mm
07-23
21.6° 15.3°
0.06 mm
07-24
23.8° 13.2°
0.06 mm
07-25
23.6° 16.5°
5.87 mm
07-26
28.6° 15.9°
1.31 mm
07-27
26.7° 21.7°
0.19 mm
Both models agree
Avg diff: 3.5°C
Where are air quality stations near St. Thomas?
44
Port Stanley, Ontario, Canada
35
Port Stanley, Ontario, Canada
42
London, Ontario, Canada
37
London, Ontario, Canada
16
London, Ontario, Canada
What cities are near St. Thomas?
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Data sources: Weather forecast from ECMWF (IFS & CAMS models). AQI calculated using US EPA standard. Updated 2026-07-21T17:17 UTC.