A previous page showed the temperature trends in various parts of New Brunswick by examining decadal mean temperatures. These 10-year means were derived from Environment Canada’s (EC) data sets; by averaging over a decade we can reduce some of the ‘noise’ resulting from annual fluctuations and determine if trends in one direction or another are apparent. The homogenized data sets provided by EC can also be used to look at decadal seasonal trends.
Seasons are defined as sets of months; with Spring being March, April, May; Summer as June, July, and August; Autumn (Fall) as September, October, and November; and Winter as December, January and February. Those definitions are important to remember as we sometimes tend to think of March, for example, as being a winter month. We also tend to speak of ‘short’ winters or ‘long’ autumns, but with these definitions the seasons are always the same duration. Thus, if January and February are colder than usual, we might say we had a ‘cold’ winter and ignore the impact on the Winter average of a mild December.
Of course, temperature is one thing, the ‘weather’ is another. A ‘mild’ winter, for example, might be warmer than average, but it also might be more miserable – if that added warmth brings more ice storms and freezing rain.
Methods used to calculate the decadal means for the four seasons were as described previously for decadal means of annual temperatures. The decadal averages were calculated by averaging each of the seasonal mean temperature for sets of 10 years.
By rolling your mouse over each decadal bar in the chart below, you can see the decadal mean temperature for a particular location. [A change in either WordPress or Google has reduced the functionality of the Google chart somewhat – those means no longer appear]
Generally speaking, when averaged by decade, the seasonal trends show similar trends to the trends for the entire year. It’s interesting, however, that for different regions, some seasons have quite striking trends whereas others are less obvious. The autumn data are interesting, especially with respect to the jump in autumn temperatures in the last decade. Winters are definitely trending warmer.
Note that the Winter chart is ‘reversed’; since the temperatures are below zero Celsius, the colder the winter mean, the longer the bar. Warmer winters, by contrast, have shorter bars.