2018 Mid-Year Review

We're 6 months into 2018, so lets take a quick look at how things have gone so far:

High Temperatures

This chart shows the High temperatures for the year.

The colourful stuff in the background of this chart is the range of temperatures that have been recorded since 1996. The average high for each day is the white line in the centre; it is surrounded by a grey band for the 25th-75th percentiles (where temperatures will fall roughly half of the time); and outside of that are the warmest temperatures since 1996 in orange and the coldest in light blue. And finally, the all-time warmest and coldest temperatures going back to 1880 are shown as the faint lines that are furthest from the average.

The red & dark blue highlighting shows days that were above or below average. Since late-April we've been pretty consistently above average, but February and April were both below.

The labels in the chart get a little crowded, but they show any days which set a recent (since-1996) record. From February through mid-April there were 6 recent-coldest High temperatures, including one all-time coldest High on April 6th at -8.6°C. And then from late-April through the end of June there were 15 recent-warmest Highs, although no all-time records.


Low Temperatures

Here we have the Low temperatures.

So far this year we've set 10 recent-coldest Lows, which were mostly clumped together in February and late-March/early-April. We've also set 10 recent-warmest Lows, including 3 all-time warmest Lows on May 8th, May 24th, and June 25th.


The Horserace

How does 2018 compare to other recent years?

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 red line for 2018 starts off warm in January, but the colder-than-average April dropped it down below the 20th century average and into the realm of other cold recent years like 2009, 2011 & 2014. Our warm June and very warm May pushed it back up again though, so now we're roughly tied with 2008 & 2013, but still on the cool side of things for recent years.


Warm & Cold Months

This chart is admittedly less about being informative, and more about being cool. But it does break down the temperatures for each year on a monthly basis, and the full explanation of what's going is in How Warm is 2017 - the Months.

This compares the average temperature for each month of 2018 to the average for the 20th century, and to the average for the last 5 years:

• The overall average temperature this January was pretty warm, at 4.2°C above the 20th century average. But most recent January's have also been pretty warm - the 5-year average is actually 5.4°C above the 20th century. So this January was 4.2°C warmer than history, but -1.2°C colder than recent years.
• February was -2.2°C below the 20th century average and -3.5°C below recent years.
• March was -0.5°C below the 20th century average and -2.2°C below recent years.
• April was -2.6°C below the 20th century average, which made it Edmonton's 23rd-coldest April. It was also -3°C below recent years.
• May was 4.7°C above the 20th century average, and the warmest May ever recorded. That also made it 2.9°C warmer than recent years.
• And June was 2.4°C above the 20th century average, or the 6th-warmest June. It was 0.5°C warmer than recent years.

So the average temperatures for January through April were all 1-3°C colder than what we'll typically get, but then May and June have both rebounded.


Precipitation

And finally, here we have the total precipitation (rain & snow) for the year so far.

At the end of 2017 we saw a large gap between Blatchford and the International Airport - with Blatchford receiving 375mm compared to 490 at the International. In 2018 we're seeing another large gap, with Blatchford at 135mm while the International is 56mm higher at 191mm. We're really just at the start of thunderstorm season though, so we'll need to see how the rest of the summer goes.