There is just no way around it: the first week of April was bitterly cold. We are talking January-and-February cold. To put it into perspective, Table 1 (further down) shows the average maximum, minimum, and mean temperatures for the first seven days of April. I’ve also included the long-term averages for this period in brackets.
As you can see, all of southern and central Manitoba has been running a good 10 C or more below the long-term average. Heck, it is almost as cold as January or February, the only difference being the strength of the sun. January’s mean monthly temperature is around -13.5 C, which is just a little bit colder than what we have seen so far this month. February’s mean monthly temperature is around -10 C, so I guess you can say it has been colder than a typical February.
The question that a lot of people have been asking, and I have heard a few discussions about on the radio, is whether this has been a record-cold start to April. To figure it out, I pulled all the April data for Winnipeg, Brandon and Dauphin, going back as far as the data goes for each station, then calculated the average maximum, minimum and mean temperatures for the first seven days of the month for each year of record. It quickly became apparent there have been several cold starts to April over the years, but three years in particular stood out: 1920, 1936 and 1979. I’m not going to lay out all the data for those three years; instead, Table 2 shows the current cold records for the three main locations for the first seven days of April.
Looking at Table 2, then comparing it to this year’s values in Table 1 (both above), you can see that only one record has been broken during this year’s cold snap: Dauphin’s average daily high of -6.9 C, which just beats out the previous record of -6.8 C. As for the rest of the records, you could say they were close, but in the world of temperature records, being off by more than 1° or 2° is not really that close. I figured I should also close a weather loophole, as some people will argue that any weather records for Winnipeg prior to 1938 can’t be fairly compared, since that was when the weather station was moved from St. John’s College to the current site. So, for those of you making that argument, Table 3 (below) has the records for Winnipeg, post-1938. Notice Winnipeg still didn’t beat the cold start to April back in 1979.
Now, the fun part: I find that once you dig up this kind of data, people now want to look back to see what the weather was like in those years. Before the advent of computer-based weather modelling, this is what long-term forecasts were based on. In Table 4 (below) I’ve listed the three years that had similar cold starts to April, along with what the weather was like for the following six months compared to average.
If you are wishing for a warmer second half of spring, then a warm summer, this data should bring you some hope. Both 1920 and 1936 saw temperatures rebound to above average in May and the above-average temperatures continued through the summer. In fact, July 1936 was the warmest month on record across southern and central Manitoba. The one fly in the ointment is 1979, when it took until June before average temperatures returned, and they only lasted until July. What I do find interesting is that the latest computer-based weather models are still sticking to their guns, calling for a gradual shift toward average temperatures through to the end of April, then moving into above-average temperatures from May through to September – much like what happened in 1920 and 1936. Now, the next question to ponder is whether we might see a repeat of the summer of 1936.