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St. Catharines (Ontario) (CA)

Air Quality Trend (last 7 days)

Good (0-50)
Moderate (51-100)
Unhealthy for Sensitive Groups (101-150)
Unhealthy (151-200)
Very Unhealthy (201-300)
Hazardous (300+)

Weather - 48h MET Norway

Cloudy
6°C
Cloudy
Humidity
89.4%
Wind
11 m/s
Pressure
1014.5 hPa
Direction
65°
Sunrise
05:00
Sunset
17:00
24h Forecast:
Temp.
5° / 16°
Precip.
22.3mm
Max wind
11.2 m/s

Hourly Forecast

11.03
Now
Weather
11
11.03
04:00
Weather
0.3
11
11.03
05:00
Weather
0.1
10
11.03
06:00
Weather
10
11.03
07:00
Weather
9
11.03
08:00
Weather
8
11.03
09:00
Weather
7
11.03
10:00
Weather
6
11.03
11:00
Weather
3.3
11.03
12:00
Weather
0.4
11.03
13:00
Weather
10°
2.9
11.03
14:00
Weather
13°
4
6
11.03
15:00
Weather
13°
2.9
6
11.03
16:00
Weather
14°
1.2
8
11.03
17:00
Weather
15°
0.5
9
11.03
18:00
Weather
16°
0.5
10
11.03
19:00
Weather
16°
2.4
9
11.03
20:00
Weather
14°
0.7
8
11.03
21:00
Weather
15°
0.7
10
11.03
22:00
Weather
14°
1.7
10
11.03
23:00
Weather
14°
10
12.03
00:00
Weather
13°
0.1
11
12.03
01:00
Weather
12°
0.2
11
12.03
02:00
Weather
0.4
11

Temperature

16°C
5°C
03:00
6°C
04:00
6°C
05:00
5°C
06:00
5°C
07:00
5°C
08:00
6°C
09:00
7°C
10:00
7°C
11:00
8°C
12:00
9°C
13:00
10°C
14:00
13°C
15:00
13°C
16:00
14°C
17:00
15°C
18:00
16°C
19:00
16°C
20:00
14°C
21:00
15°C
22:00
14°C
23:00
14°C
00:00
13°C
01:00
12°C
02:00
6°C
03:00 14:00 02:00

Precipitation

4mm
0mm
04:00
0.3mm
05:00
0.1mm
11:00
3.3mm
12:00
0.4mm
13:00
2.9mm
14:00
4mm
15:00
2.9mm
16:00
1.2mm
17:00
0.5mm
18:00
0.5mm
19:00
2.4mm
20:00
0.7mm
21:00
0.7mm
22:00
1.7mm
00:00
0.1mm
01:00
0.2mm
02:00
0.4mm
03:00 14:00 02:00

Wind

11.2m/s
0m/s
03:00
11.1 m/s
04:00
10.8 m/s
05:00
10.1 m/s
06:00
9.9 m/s
07:00
9.2 m/s
08:00
8 m/s
09:00
6.9 m/s
10:00
5.9 m/s
11:00
4.5 m/s
12:00
4.8 m/s
13:00
5 m/s
14:00
6.4 m/s
15:00
6.2 m/s
16:00
8.2 m/s
17:00
9 m/s
18:00
10.2 m/s
19:00
9 m/s
20:00
8.3 m/s
21:00
9.6 m/s
22:00
10.2 m/s
23:00
9.7 m/s
00:00
10.5 m/s
01:00
10.7 m/s
02:00
11.2 m/s
03:00 14:00 02:00

Radiation

0.015 uSv
3.8 km
1.8%

Measurement time: 2026-03-11 02:00

source: remap_europe

We display the worst measurements from all stations in the area. This approach provides a more cautious assessment of air quality, accounting for local pollution sources.

AQI
85.2 km
88
29.3%

Measurement time: 2026-03-11 05:00

Calculated from PM2.5/PM10

PM2.5
85.2 km
30 µg/m3
35.7%

Measurement time: 2026-03-11 05:00

source: Aqicn

O3
85.2 km
20 µg/m3
12.5%

Measurement time: 2026-03-11 05:00

source: Aqicn

NO2
53.6 km
10.2 µg/m3
5.1%

Measurement time: 2026-03-11 05:00

source: Aqicn

SO2
69.3 km
0.3 µg/m3
0.1%

Measurement time: 2026-03-11 05:00

source: Aqicn

Info


Country: Canada
Region: Ontario
Latitude: 43.17126
Longitude: -79.24267

Cities in the area:

About Air Quality in St. Catharines

Air quality in St. Catharines is monitored in real-time by sensors and measurement stations. On this page you'll find current data on major air pollutants including particulate matter PM2.5 and PM10, nitrogen dioxide (NO2), ozone (O3), and radiation levels.

Common Pollutants in St. Catharines

  • PM2.5 - fine particulate matter up to 2.5 micrometers, particularly harmful to health
  • PM10 - particulate matter up to 10 micrometers from traffic and industry
  • NO2 - nitrogen dioxide mainly emitted by vehicles
  • O3 - tropospheric ozone formed in photochemical reactions

When is Air Quality Best in St. Catharines?

Generally, the best air quality occurs:

  • Early morning (5:00-7:00 AM) before rush hour traffic
  • After rainfall which cleanses the atmosphere
  • During strong winds that disperse pollutants
  • In summer months when heating systems are less used

Tips for Runners in St. Catharines

If you're planning outdoor activities in St. Catharines, always check the current AQI value. When AQI exceeds 100, consider moving your workout indoors or shortening the distance. People with respiratory issues, children, and seniors should be especially cautious during elevated pollution levels. Choose routes away from busy streets and industrial areas.