The minimum number of years used to calculate these Normals is indicated by a code for each element. A "+" beside an extreme date indicates that this date is the first occurrence of the extreme value. Values and dates in bold indicate all-time extremes at the location for that reporting period. Normal period extremes (NPE) are calculated for the 30-year normal period, whereas long-term extremes (LTE) extend further back in time to the earliest date available in the data series.
Data used in the calculation of these Normals may be subject to further quality assurance checks. This may result in minor changes to some values presented here.
Probability of last temperature in spring <= 0°C, on or after (Date)
May 15
May 07
May 04
Apr 28
Apr 21
Apr 17
Apr 09
Probability of first temperature in fall <= 0°C, on or before (Date)
Oct 01
Oct 10
Oct 13
Oct 19
Oct 26
Nov 01
Nov 11
Probability of frost-free period equal to or less than indicated period (Days)
144
158
163
174
187
193
207
Legend
A = WMO "3 and 5 rule" (i.e. no more than 3 consecutive and no more than 5 total missing for either temperature or precipitation)
B = At least 25 years
C = At least 20 years
D = At least 15 years
+ = Most recent occurrence of the extreme value
Element Analytics
Statistics listed below are provided as a guide to determine the validity of Normals and Extremes calculations. For example, a composite station with 30 years of record between 1991 and 2020 with no missing years would be a more reliable normal than a composite station with 15 years of record and 2 missing years. Less than 100% possible observations indicates that out of the total number of observations used, some records were missing.
Probability of last temperature in spring <= 0°C, on or after (Date)
10 %
1841
2011
169
98.8
25 %
1841
2011
169
98.8
33 %
1841
2011
169
98.8
50 %
1841
2011
169
98.8
66 %
1841
2011
169
98.8
75 %
1841
2011
169
98.8
90 %
1841
2011
169
98.8
Probability of first temperature in fall <= 0°C, on or before (Date)
10 %
1841
2011
169
98.8
25 %
1841
2011
169
98.8
33 %
1841
2011
169
98.8
50 %
1841
2011
169
98.8
66 %
1841
2011
169
98.8
75 %
1841
2011
169
98.8
90 %
1841
2011
169
98.8
Probability of frost-free period equal to or less than indicated period (Days)
10 %
1841
2011
169
98.8
25 %
1841
2011
169
98.8
33 %
1841
2011
169
98.8
50 %
1841
2011
169
98.8
66 %
1841
2011
169
98.8
75 %
1841
2011
169
98.8
90 %
1841
2011
169
98.8
Composite Metadata / Threads
The Climate Normals, Averages, and Extremes are based on Canadian climate composite stations with at least 15 years of data between 1991 and 2020. Composite stations are comprised of one or more stations operated by the Meteorological Service of Canada (MSC) or its partners, where data from individual stations are joined together to create a 30-year data series for a given location. All stations (and associated metadata) used as part of the composite are listed below, alongside the threads used to calculate each Normals/Extremes element.
All stations used in the composite for all Normals and Extremes elements are listed. Station metadata includes station name, station identifiers, coordinates, and elevation.
Station composites are threaded from the beginning of the Normals period starting in 1991 to the end of 2020, where the predecessor site's data is used until the end of its period of record and is then joined to the current operating site to extend the time series. Threads are generated by climate element for hourly and daily data, and may vary due to differences in station history, instrumentation, meteorological data availability, data quality, or proximity.
Normals and Extremes elements are grouped based on the climate element used in its calculation. Normal period extremes (NPE) are calculated using threads for the 30-year normal period. For long-term (LT) elements and long-term extremes (LTE), the same Normals period threads are extended back in time to the earliest date of data available from the first station used in the data series. These use the 'LTE Start Date' instead of the 'Start Date', that applies to normals period elements and extremes (NPE).
