High Temperatures
For most of the year we never quite know what Edmonton's weather will throw at us, but July is relatively predictable. The High temperatures fall into a narrow band, and this July they just bounced around the average a bit with the coldest High at 17.8°C on July 2nd, and the warmest at 32.3°C on the 17th.
We didn't set any all-time records this month, but we did set two recent (since 1996) records on July 6th at 30.1°C and July 16th at 30.7°C. That's down a bit from June where we set 6 recent records, and May where we set 8.
This July our average High temperature was 24.8°C which is on the warm-side of recent years, although July 2007 is the real standout with an average of 26.6°C.
We had 27 days which hit 20°C, and that's just a bit above the average of 25 days. We also had 17 days at 25°C compared to an average of 12, and 4 days at 30°C compared to an average of 2.
In the last few months we looked at how May & June were both bonus-Julys because they had so many warm days: May had 23 days at 20°C & 13 days at 25°C; and June had 25 days at 20°C & 11 days at 25°C. July did end up beating both of those months, but the numbers were a lot closer than normal.
Hot Days So Far...
This chart shows how many "hot" days we had each year going back to 1880. In Edmonton's Hottest Days we saw that the number of really hot 30°C+ days hasn't actually changed much over the years. But 2014, 2015, 2016 and 2017 all had a lot of "warm" 25°C days, even compared to 5 years ago.
That streak of 25°C days has continued into 2018 with 42 so far, and the summer isn't over yet. For August we average 10 days which hit 25°C, and for September it's another 3 days. So if August & September this year are average then 2018 could end up with around 55 days at 25°C. The record for Edmonton was 64 days set in 1898, but 55 days would put 2018 in the top-5.
Low Temperatures
July's Low temperatures fall into an even narrower band than the Highs do. This month's coldest Low was 8.2°C on the 21st, and the warmest was only about 8°C warmer at 16.5°C on the 17th. And once again there were no all-time records, but we set a recent-warmest Low of 16.4°C on the 6th and a recent-coldest Low of 8.2°C on the 21st.
Normally with this table you can use the different colours to see how the temperatures are distributed. In July it's just a whole bunch of orange though, because that range of temperatures is so narrow - in the last 20 years the coldest July Low was 6°C and the warmest was 21°C.
The Horserace
This chart tracks how much warmer each day of the year was compared to the 20th century average - warm days get points and cold days lose them. The blue and orange background is the range of all the years going back to 1880, and each of the last 10 years is shown as an individual line. For a full explanation of this chart it's easiest to refer back to the original discussion of it in How warm is 2016? (September Edition).
The early part of 2018 was pretty cold, but things have warmed up recently: May was the warmest overall May recorded since 1881, June was the 6th-warmest June, and now July was Edmonton's 15th-warmest July.
Back in April our cumulative temperature for the year was colder than the 20th century average, but the last 3 warm months have just pushed 2018 up to the 75th percentile.
This chart goes back to 2000, and it shows how the average temperatures (High & Low) for each month compares to the 20th century average; to the 5-year average; and to 2018.
For the summer of 2018 May, June and July were all on the positive side of things. And that also happened in 2015, 2016 and 2017, and so we've now had a string of 4 years with warm May-July. But that's also a little uncommon, because the only other years here where that happened were 2006 and 2008.
Precipitation
This chart shows how many days in July recorded rain, and the International Airport was right on the average with 15, while Blatchford was down at 12.
In terms of total rain recorded though, both stations were below the July average of 93mm, with the International at 64.6mm and Blatchford just a bit higher at 67.8mm.
For the year that brings the International's total precipitation to 255mm, which is on the low-side of things and right at the 25th percentile. And Blatchford missed some of the May and June rain, so it is down at 202mm, which is pretty dry. Other recent dry years were 2002 which was at 157mm on July 31st, and 2009 which was at 177mm.
August Temperatures
Our average temperature for the year top-out at around July 22, and start trending downwards through August.
In August most of the daytime highs will still be above 20°C, and we'll get a week or two above 25°C. 30°C days are a little rare though, and about half of the time August won't have any. For the Low temperatures it should be a lot of the same 10-20°C orange which we saw for July, but with a few more nights in the 5-10°C range, and every 5 years-or-so a night below 5°C.
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