May Review / June Preview

At this time last year I talked about how warm May 2016 was, but May 2017 topped it.

May High Temperatures

Does anyone remember April? April was not warm. But once we hit May the temperatures took off.

We had one all-time record on May 5 at 28.9°C, and then six other recent-records, including May 30 and May 31. And the International also had an all-time record on May 31st, at 31.2°C (but those records only goes back to the 1960s)

We were above average for most of the month, except for a few rainy days from the 13th through 17th.

Our average High this month was 20.5°C, which is the 2nd-warmest of recent years, coming in just behind 1998 at 21.2°C.

Compared to other recent years, we also had the 2nd-most days above 20°C at 18, and the most days above 25°C at 7. And we even managed one day above 30°C, on the last day of the month.

When we get a genuinely hot day in May it always feels like a surprise. In reality though, it's pretty typical to get at least a day or two above 25°C - since 1998 there were only 5 times that May didn't break 25°C. And then on the flipside, since 1998 there were 5 Mays that broke 30°C.

One other thing to notice is that in each of the last 3 years we've had almost a week of days above 25°C, which is well above the average, and makes it feel like summer has started a little early.

May Low Temperatures

The Lows were pretty similar to the highs: 1 all-time record on May 5, and then 5 other recent-records later in the month.

The average Low for this month was 7.5°C, again coming in a bit below 8.5°C for 1998. And we didn't have any Lows below freezing, which had only happened 5 other times since 1998.


This May there were 8 days with recorded precipitation, which is a little below the average for May, and half of what we just saw in April.

We also had a snow-free May this year, which only happens a little less than half of the time.

In terms of precipitation totals, with 71.7mm we were above the recent May average and right at the 75th percentile. More than half of that fell during a single day though, with 44.6m on the very rainy May 24th. These numbers are from the International Airport, and inside the city at Blatchford there was only 55.5mm recorded this month, with 32.4mm of that during the May 24th storm.

In this chart there's also a line for 2016, as a reference. Last year we had a very dry April, a very rainy May, and then a pretty average June and July.

June Temperatures

Before I started this blog, I had always had the impression that June was often cold. I don't know where I got that impression though, because it's really not the case. The coldest High since 1998 was 8°C in 2000, and in the past 19 years there have only been 2 other June days which didn't break 10°C. And for Lows, the coldest June day here dropped to 2°C, while only about half of these years had any Lows below 5°C.

So as we head into June our temperatures will typically be pretty similar to what we just saw this May. And that might actually be why I think of June as cold - if we get a below-average June this year that might seem cold compared to the warm May that we just had.

But in a typical June about half of the month is above 20°C, with maybe a week's worth of days above 25°C. There are some warm Junes like last year with 13 days above 25°C, and cooler ones like 2011 with only 1. And the average rainfall for June is 73mm, which is very similar to what we just had in May.

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