Weather Email Bag

Jan. Feb. Mar. Apr. May. Jun. Jul. Aug. Sep. Oct. Nov. Dec. Avg.

10.2 9.9 10.7 12.1 12.3 9.1 7.9 8.3 8.5 10.2 10.9 10.4 10.0

Average monthly wind speeds (km/h)

The Weather Vane is prepared by Daniel Bezte, a teacher by profession with a B. A. (Hon.) in geography, specializing in climatology, from the University of Winnipeg. Daniel has taught university-level classes in climate and weather and currently operates a computerized weather station at his home near Birds Hill Park, on 10 acres he plans to develop into a vegetable and fruit hobby farm.

Contact him with your questions and comments at [email protected]

I’ve received a fair number of emails over the last month, so I think this week we will go to this electronic mailbag and look into some of the different issues readers have had.

For the first email I want to thank Jay Scott over at MARFI for sharing with me some of the snow-cover and snow-depth observations he had heard about from farmers south of the border. After hearing what these farmers had to say about some of the incredible snow depths in parts of North Dakota, I did some more digging and found an updated snow map that covers the states that border Canada. I have included this map here and from it you can see that a good chunk of central North Dakota has between 50 and 100 cm of snow still sitting in the ground as of March 15; that is a lot of potential water!

The second email I want to address was one that asked about wind speeds this winter. The reader felt that this winter didn’t seem to be very windy. When I received this email I thought, no problem, I will just look up wind speed averages and then compare them to what our three main locations recorded this winter. Boy was I wrong. Trying to find useful wind data proved to be much harder than I thought.

The first question I had to ask myself was what kind of wind data would be most useful? To me, the most useful data would be average daily and then monthly wind speeds. So off to EC’s website to find the data… but no luck, EC only shows data on wind gusts, nothing on average wind speeds. I was able to find what looked to be long-term average wind speed data for our three main locations from Environment Canada, but I was not able to determine how these values were calculated. These values indicated that for most months in southern Manitoba the average wind speed is around 20 km/h.

At first glance this value doesn’t sound too bad, but then I compared it to my own wind speed data and the numbers didn’t even come close to agreeing. My weather station records daily average wind speed along with monthly averages. My anemometer is located seven metres off the ground and my location is fairly open, so it is usually fairly windy (some days you end up cursing the wind). When I compared my average wind speed data to what I found at EC I discovered that my values where about 50 per cent lower. In fact, my windiest month ever was still lower than EC’s average monthly wind speed. I have put out some requests to see if I can get an explanation of how EC calculates its data and I will hopefully be able to update you next week.

Regardless of this difference, what I think was the biggest surprise was how little month-to-month variation there was in wind speeds across southern Manitoba. Using my data set, below are the monthly average wind speeds.

From this data we can see that the March to May period tends to be the windiest, while the summer months are the calmest and winter winds are fairly consistent.

Now back to the email question about wind, was the winter of 2009-10 less windy than average? Well, at my location, December was definitely less windy with an average monthly speed of 8.4 km/h. January was a little windier than average with a value of 10.9 km/h. Finally, February also came in below average with an average monthly wind speed of 7.8 km/h. So, looking at this data in this way I would say that overall wind speeds this winter were below average. Combine this with near-to above-average temperatures this winter and we ended up with a winter feeling even nicer than it was.

Next week we will take a look at spring frost. I know it is a little early, but I’d rather look at frost than examine the top biggest spring snowstorms!

About the author

Co-operator contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the U of W. He operates a computerized weather station near Birds Hill Park.

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