July 2016 Rainfall

The rain was in the news a lot last month, with what seemed like constant thunderstorm watches, and the emergency canoes were even called out a few times to save people from the flooded Whitemud.

So it seemed like a really rainy July, but was it? It depends a bit on exactly where you were:

The chart shows the cumulative rainfall totals for four of the stations around Edmonton:
  • International Airport - 102mm
  • Blatchford - 88mm
  • UofA - 86.2mm (unfortunately data is missing for the final 4 days)
  • Stony Plain - 69.6mm
The totals for the month vary by station, but we can also see that different stations got hit on different days. The International received more rain right at the beginning and the end of the month than the other stations, but the big storm on the 26th mostly missed it.

That storm on the 26th was the first of the Whitemud floods this year, and at least one local weather station recorded 60mm in just a few hours. None of these Environment Canada stations show anything quite that significant though, with the largest one-day rainfall recorded as 39mm on July 30 at the International Airport.

So rainfall definitely varies by location, but for the rest of today I'm just going to stick with the International. Of these four stations it had the highest numbers (excluding the UofA and its missing data), and it's the station that I have all the historic charts setup for.

In terms of number of rainy days, this year was a little above the average with 17 days of recorded rainfall. The 20-year average is 15, but the maximum was 23 in 1996, so this year was quite typical.

Anecdotally, I have a four year old dog who hates thunder, and this year broke her brain. She's lived through three mostly quiet summers, but this July's night-after-night thunder sent her scurrying to hide in the bathroom most evenings.

In terms of amount of rain, the 102mm at the International put us just a little bit above the average, and just a little below this year's total for May.

And this chart compares July rainfall totals for each year going back to 1985. Each column is divided by week to give a sense of roughly when the rain fell. And 2016 is right inline with 2012-2015, and below 2010 and 2011.

For a truly rainy July, we can take a look at Calgary:

This is the same chart as the previous one, but with a line added to show the rainfall for the Calgary International. Normally Calgary gets less rain in July than Edmonton does - in 22 of the last 30 years Edmonton has had more, and Edmonton averages 93mm compared to 69mm in Calgary.

But in July 2016 Calgary received 206mm of rain, which doubled Edmonton's numbers, and tripled their average. Prior to 2016, their rainiest July in the last 30 years had only had 133mm of rainfall. So Calgary definitely had a rainy July this year - and in comparison Edmonton's was very average.

Finally, here's where Edmonton's total precipitation for the year sits. The May long weekend pushed us up above average, and since then we've tracked pretty closely along the average line. Then right at the end of July the International got a few big storms to boost things up a bit more.

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