April Review / May Preview - Part 1 - Temperatures

And that's the end of April, 2017.

So just how cold was it, really?

High Temperatures

Here we have the High temperatures for the last two months, how they compared to the records, and how much time we spent above or below the average.

Early-April feels like it was a long time ago now, and it's easy to forget that the month actually started off quite warm. On April 5th we hit 15.3°C which was the warmest April 5th that we've had recently, although still well below the all-time record of 22.2°C from back in 1905. April 6th was a bit little warmer than that at 16.5°C, which was the warmest day of the month.

Later in the month we were pretty solidly below the average, and had two coldest-recent days, on April 18th and 26th.

Let's take a closer look at the numbers:

With an average high of 8°C, 2017 is certainly in the lower-tier of recent Aprils. April 2013, 2011 and 2008 were all about this cold, and 2002 was even colder.

15-of-the-last-20 Aprils have had at least one day above 20°C, but in 2017 we didn't get any. We also only had 3 days above 15°C, and two of those were way back at the beginning of the month. We only had one High below 0°C though, unlike 2002 and 2008 which both had daytime Highs down around -10°C.

Other Cold Aprils

For comparison, here are the temperatures from some of the other cold, recent Aprils:

• 2013 started and ended colder than this year, and in the middle was pretty similar.
• 2011 was pretty similar - a little colder at the beginning, and a little warmer near the end.
• 2008 dipped to some all-time lows around April 20th. 
• And 2002 started much colder than 2017, but then the last 3 weeks were almost a perfect match to what we've just seen.

I don't have any particular recollection of those Aprils, but I assume people were as eager for spring to get started as they were this year.

Low Temperatures

Compared to the High temperatures, the Lows this month were pretty boring.

At the beginning of the month we were close to a few recent warmest nights, but later in the month we just hung around slightly below the average. And then right at the end of the month on April 30th we had a warmest-recent Low at 5.8°C.

This April there were 15 Lows below freezing, but only one of those was below -5°C. That's quite a bit warmer than 2002 and 2008, which both had 5 Lows below -10°C. The average overnight Low of 0°C for the month puts 2017 right in the middle of recent Aprils.

May Temperatures

As we head into May, temperatures should take another step up (although I said the same thing about April...).

Since 1998 we haven't had a day in May which didn't at least break the freezing mark - the coldest were a few daytime Highs around 1°C back in 2003. Based on previous years we should see a week or two above 20°C, and about three-quarters of the time at least one day in May will hit 25°C. A 30°C day even happens about one-quarter of the time, most recently in 2016 and 2013.

For Low temperatures, about a quarter of the time May will have no lows below 0°C, although more typically there are a a handful. In recent years the coldest May nights were -6°C, back in 2002.

Finally for today, here's the latest topographical representation of the last 20 years of Edmonton High temperatures. I've been doing these for the past few months, and with the addition of May we see the temperatures continuing to rise, and the overall landscape continuing to flatten out with less wild variations. I know this thing doesn't make a lot of sense, but in a few weeks I'll look at it in more detail, to try to give it a bit more context.

That's it for today's look back at the temperatures of April, 2017. The big story this month was actually probably precipitation, and we'll be back to look at that later in Part 2.