Observed at: St. Catharines / Niagara District Airport
Date: 12:00 AM EDT Wednesday 20 May 2026
Temp.: 19 °C
Wind: SW 30 gust 44 km/h
Humidity: 86 %
Dew point: 17 °C
Pressure: 101.3 kPa
Tendency: kPa
Visibility: km 		Sunrise: 5:49
Sunset: 20:39
Normals:
Max 20°C Min 10°C
 Extended Forecast - Environment Canada
  Wed, 20 May
Chance of showers (40%)
Chance of showers
Max: 17°C
 Thu, 21 May
Sunny
Sunny
Max: 13°C
 Fri, 22 May
Cloudy
Cloudy
Max: 17°C
 Sat, 23 May
Showers
Showers
Max: 16°C
 Sun, 24 May
Chance of showers (40%)
Chance of showers
Max: 16°C
 Mon, 25 May
A mix of sun and cloud
A mix of sun and cloud
Max: 20°C
Tonight
Chance of showers (40%)
Chance of showers
Min: 13°C
 Night
Clear
Clear
Min: 6°C
 Night
Clear
Clear
Min: 9°C
 Night
Cloudy
Cloudy
Min: 13°C
 Night
Cloudy
Cloudy
Min: 11°C
 Night
Cloudy
Cloudy
Min: 12°C

Forecast

St. Catharines, ON (Issued: 10:27 PM EDT Tuesday 19 May 2026)

Tonight
Showers ending near midnight then cloudy with 40 percent chance of showers. Wind southwest 20 km/h gusting to 40 becoming northwest 20 gusting to 40 after midnight. Low 13.
Wed, 20 May
Mainly cloudy. 40 percent chance of showers early in the morning. Clearing in the morning. Wind northwest 20 km/h gusting to 40. High 17. UV index 9 or very high.
Night
Clear. Wind north 20 km/h. Low 6.
Thu, 21 May
Sunny. High 13.
Night
Clear. Low 9.
Fri, 22 May
Cloudy. High 17.
Night
Cloudy. Low 13.
Sat, 23 May
Showers. High 16.
Night
Cloudy. Low 11.
Sun, 24 May
Cloudy with 40 percent chance of showers. High 16.
Night
Cloudy. Low 12.
Mon, 25 May
A mix of sun and cloud. High 20.

24 Hour Forecast - St. Catharines, ON

Date/Time Temp.
(°C)
Weather Conditions
LOP †		 Wind
(km/h)
20 May 2026
1 AM 18 Chance of showers (40%)  Chance of showers 40 SW 20 gust 40
2 AM 18 Chance of showers (40%)  Chance of showers 40 NW 20 gust 40
3 AM 18 Chance of showers (40%)  Chance of showers 40 NW 20 gust 40
4 AM 17 Chance of showers (40%)  Chance of showers 40 NW 20 gust 40
5 AM 17 Chance of showers (40%)  Chance of showers 40 NW 20 gust 40
6 AM 16 Chance of showers (40%)  Chance of showers 40 NW 20 gust 40
7 AM 14 Chance of showers (40%)  Chance of showers 40 NW 20 gust 40
8 AM 13 Mainly cloudy (20%)  Mainly cloudy 20 W 20
9 AM 13 A mix of sun and cloud (20%)  A mix of sun and cloud 20 W 20
10 AM 14 Mainly sunny (20%)  Mainly sunny 20 W 20
11 AM 14 Sunny (20%)  Sunny 20 W 20
12 PM 15 Sunny (0%)  Sunny 0 W 20
1 PM 15 Sunny (0%)  Sunny 0 W 20
2 PM 16 Sunny (0%)  Sunny 0 NW 20
3 PM 16 Sunny (0%)  Sunny 0 NW 20
4 PM 17 Sunny (0%)  Sunny 0 NW 20
5 PM 17 Sunny (0%)  Sunny 0 N 15
6 PM 16 Sunny (0%)  Sunny 0 N 15
7 PM 14 Sunny (0%)  Sunny 0 N 15
8 PM 13 Sunny (0%)  Sunny 0 N 20
9 PM 11 Clear (0%)  Clear 0 N 20
10 PM 10 Clear (0%)  Clear 0 N 20
11 PM 8 Clear (0%)  Clear 0 N 10
21 May 2026
12 AM 8 Clear (0%)  Clear 0 N 10
 
† 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