A fun chart

Nothing too profound today. A few weeks ago the New York Times had a fun animation showing how summer temperatures in the Western Hemisphere have changed over the last half-century. I can't find a way to embed the animation, but the story is worth a read, and here's one screenshot:

Source: New York Times, July 28 2017, It’s Not Your Imagination. Summers Are Getting Hotter.
By NADJA POPOVICH and ADAM PEARCE

The chart and data come from Dr. James Hansen, and the background behind it be found here:
Global Temperature in 2015

I was curious what something similar would look like for Edmonton, so here is my version:

This shows roughly how the High temperatures in Edmonton are distributed for June through August. This chart is smoothed a bit

Since the 1950s things have been pretty consistent:

• about one-third of summertime Highs are below 20°C
• 40-44% of the time the Highs are from 20°C to 25°C
• 20-25% of the time the Highs are from 25°C to 30°C is 
• and about 4% of the time we break 30°C (3 to 4 days each summer)

In the last ten years the most notable change was that the number of Highs below 20°C was lower than normal, at 27%. So that shifts the 2007-2016 distribution to the right a bit compared to all the others. But honestly, it's not as dramatic as I would have hoped.

If we switch from decades to individual years things move around a bit more:

Yearly Comparison

This give a sense of the variety of summers over the last decade.

Both 2010 and 2011 were pretty cool, with less than 20% of the Highs above 25°C. More typically it's somewhere around 30%. And the summer of 2015 was above 25°C for 47% of the time.

For the Highs below 20°C, in 2015 it was 14% of the summer, and in 2016 it was only 12%. That's well below the 30-35% which is more typical. For some context, since we're looking at the 92 days from June-August, that means a difference of 20% is equivalent to about 18 days.

These charts are fun, although I think it's actually a little difficult to spot trends or make good comparisons from them. For that, I still prefer this type:

We've looked at this chart before here, and it's a comparison of the temperatures for the entire year, rather than just for the summer.

In a couple weeks we'll check in on 2017 to see how it compares so far.