Rainfall Warning
2:16 p.m. EDT Thursday 22 May 2025

Rainfall Warning in effect for:
  • St. Catharines - Grimsby - Northern Niagara Region
What:
Rain, at times heavy, is expected.

Hazard:
Total rainfall amounts of 50 to 60 mm.

Timing:
Through this afternoon.

Additional information:
Near 30 mm rain has been reported as of this morning in this area. Additional 20 to 30 mm rain is expected before rain tapers off to showers this evening.

Localized flooding in low-lying areas is possible.

Watch for possible washouts near rivers, creeks and culverts.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ONstorm@ec.gc.ca or post reports on X using #ONStorm.

Observed at: St. Catharines / Niagara District Airport
Date: 5:00 PM EDT Thursday 22 May 2025
Light Rain
Light Rain
Temp.: 11 °C
Wind: S 14 km/h
Humidity: 97 %
Dew point: 11 °C
Pressure: 100.4 kPa
Tendency: 0.04 kPa
Visibility: 13 km
Sunrise: 5:47
Sunset: 20:41
Normals:
Max 21°C Min 10°C
 Extended Forecast - Environment Canada
  Fri, 23 May
Periods of rain
Periods of rain
Max: 13°C
Sat, 24 May
Cloudy
Cloudy
Max: 12°C
Sun, 25 May
A mix of sun and cloud
A mix of sun and cloud
Max: 15°C
Mon, 26 May
A mix of sun and cloud
A mix of sun and cloud
Max: 17°C
Tue, 27 May
Cloudy
Cloudy
Max: 15°C
Wed, 28 May
Chance of showers (60%)
Chance of showers
Max: 15°C
Tonight
Periods of rain
Periods of rain
Min: 9°C
Night
Chance of showers (40%)
Chance of showers
Min: 8°C
Night
Cloudy periods
Cloudy periods
Min: 8°C
Night
Cloudy periods
Cloudy periods
Min: 9°C
Night
Cloudy periods
Cloudy periods
Min: 11°C
Night
Chance of showers (60%)
Chance of showers
Min: 11°C

Forecast

St. Catharines, ON (Issued: 3:30 PM EDT Thursday 22 May 2025)

Tonight
Periods of rain. Amount 5 to 10 mm. Wind becoming west 20 km/h gusting to 40 after midnight. Low 9.
Fri, 23 May
Periods of rain ending in the afternoon then cloudy with 40 percent chance of showers. Amount 5 mm. Wind west 20 km/h gusting to 40. High 13. UV index 2 or low.
Night
Cloudy with 40 percent chance of showers. Wind west 20 km/h gusting to 40. Low 8.
Sat, 24 May
Cloudy. High 12.
Night
Cloudy periods. Low 8.
Sun, 25 May
A mix of sun and cloud. High 15.
Night
Cloudy periods. Low 9.
Mon, 26 May
A mix of sun and cloud. High 17.
Night
Cloudy periods. Low 11.
Tue, 27 May
Cloudy. High 15.
Night
Cloudy with 60 percent chance of showers. Low 11.
Wed, 28 May
Cloudy with 60 percent chance of showers. High 15.

24 Hour Forecast - St. Catharines, ON

Date/Time Temp.
(°C)

Weather Conditions

LOP †
Wind
(km/h)
22 May 2025
6 PM 14 Periods of rain (80%)  Periods of rain 80 S 10
7 PM 13 Periods of rain (80%)  Periods of rain 80 S 10
8 PM 12 Periods of rain (80%)  Periods of rain 80 VR 5
9 PM 12 Periods of rain (80%)  Periods of rain 80 VR 5
10 PM 11 Periods of rain (80%)  Periods of rain 80 VR 5
11 PM 11 Periods of rain (80%)  Periods of rain 80 W 10
23 May 2025
12 AM 11 Periods of rain (80%)  Periods of rain 80 W 10
1 AM 10 Periods of rain (80%)  Periods of rain 80 W 10
2 AM 10 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
3 AM 10 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
4 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
5 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
6 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
7 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
8 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
9 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
10 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
11 AM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
12 PM 9 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
1 PM 10 Periods of rain (80%)  Periods of rain 80 W 20 gust 40
2 PM 10 Chance of showers (40%)  Chance of showers 40 W 20 gust 40
3 PM 11 Chance of showers (40%)  Chance of showers 40 W 20 gust 40
4 PM 12 Chance of showers (40%)  Chance of showers 40 W 20 gust 40
5 PM 13 Chance of showers (40%)  Chance of showers 40 W 20 gust 40
 
† Likelihood of Precipitation (LOP) as described in the public forecast as a chance of measurable precipitation for a period of time.
  Nil: 0%
  Low: 40% or below
  Medium: 60% or 70%
  High: Above 70%

Environment Canada