St. Catharines Temperatures: Averages by Month
The numbers here tell you how hot and cold the weather usually is in St. Catharines, Ontario during each month of the year.
The average high and low temperatures are listed below monthly and annually for the city, in both degrees Fahrenheit and Celsius.
Maximums and minimums are only part of the temperature picture. To fill in the rest, there's information on how many days a month get above or below a given temperature.
To find out how often it rises over 10, 20 or 30 °C each month in St. Catharines, scroll down farther. There are also monthly and yearly counts of days with frost and cold weather.
The first set of high and low temperatures are averages for 2010 to 2019. Everything else here is based on 1981 to 2010 weather.
| High °F | Low °F | High °C | Low °C | |
|---|---|---|---|---|
| 33 | 22 | January | 1 | -5 |
| 34 | 23 | February | 1 | -5 |
| 41 | 29 | March | 5 | -2 |
| 52 | 38 | April | 11 | 3 |
| 63 | 48 | May | 17 | 9 |
| 72 | 59 | June | 22 | 15 |
| 80 | 66 | July | 27 | 19 |
| 78 | 66 | August | 26 | 19 |
| 72 | 60 | September | 22 | 16 |
| 61 | 49 | October | 16 | 10 |
| 48 | 37 | November | 9 | 3 |
| 38 | 30 | December | 4 | -1 |
| 56 | 44 | Year | 13 | 7 |
| High °F | Low °F | High °C | Low °C | |
|---|---|---|---|---|
| 32 | 19 | January | 0 | -7 |
| 34 | 20 | February | 1 | -7 |
| 42 | 26 | March | 5 | -3 |
| 54 | 36 | April | 12 | 2 |
| 67 | 46 | May | 19 | 8 |
| 76 | 56 | June | 24 | 13 |
| 81 | 62 | July | 27 | 17 |
| 78 | 60 | August | 26 | 16 |
| 71 | 53 | September | 22 | 12 |
| 59 | 42 | October | 15 | 6 |
| 47 | 34 | November | 8 | 1 |
| 37 | 24 | December | 3 | -4 |
| 56 | 40 | Year | 14 | 4 |
Days of Hot Weather in St. Catharines
The hottest days at St. Catharines usually have temperatures peaking in the low-thirties Celsius. The city averages 14 days a year with thirty-degree weather, which can show up from April to September. The temperature does climb above 35 °C (95 °F) on an average of one day in two or three years.
| 10 °C 50 °F |
20 °C 68 °F |
30 °C 86 °F | |
|---|---|---|---|
| January | 1 | 0 | 0 |
| February | 2 | 0 | 0 |
| March | 7 | 1 | 0 |
| April | 19 | 3 | 0 |
| May | 30 | 13 | 1 |
| June | 30 | 26 | 3 |
| July | 31 | 30 | 7 |
| August | 31 | 30 | 3 |
| September | 30 | 18 | 1 |
| October | 26 | 5 | 0 |
| November | 10 | 1 | 0 |
| December | 3 | 0 | 0 |
| Year | 219 | 127 | 14 |
When St. Catharines Has Frosty Weather
St. Catharines typically has 127 days a year when the minimum temperature is at 0 °C or below. The average date for the last frost in spring is April 24. Frost normally returns here on October 21. The frost-free period extends for 179 days on average between the final spring frost and the first fall frost.
| 0 °C 32 °F | |
|---|---|
| January | 28 |
| February | 25 |
| March | 23 |
| April | 9 |
| May | 0 |
| June | 0 |
| July | 0 |
| August | 0 |
| September | 0 |
| October | 3 |
| November | 14 |
| December | 25 |
| Year | 127 |
How Often St. Catharines Has Cold Temperatures
The chilliest winter nights at St. Catharines have lows in the minus-twenties °C (below -3 °F). But the city averages only one night a year, usually in January, when it gets that cold. Temperatures down to -30 °C (-22 °F) are not normal here.
From November to April, St. Catharines can remain below freezing all day long. The city typically has 100 days a year when the temperature never rises above 0 °C.
| -2 °C 28 °F |
-10 °C 14 °F | |
|---|---|---|
| January | 25 | 10 |
| February | 22 | 8 |
| March | 18 | 3 |
| April | 3 | 0 |
| May | 0 | 0 |
| June | 0 | 0 |
| July | 0 | 0 |
| August | 0 | 0 |
| September | 0 | 0 |
| October | 1 | 0 |
| November | 7 | 0 |
| December | 19 | 4 |
| Year | 94 | 27 |
References
Environment Canada. Meteorological Service of Canada. Canadian Climate Normals. 1981-2010 Climate Normals & Averages.
Jay Lawrimore, Ron Ray, Scott Applequist, Bryant Korzeniewski, Matthew Menne. 2016. Global Summary of the Month and Year, Version 1.0. NOAA National Centers for Environmental Information.