Earth Sciences and Ecology Question #571

Thalia Parcs, a 27 year old female from Toronto asks on January 21, 2002,

I have noticed in Toronto for the past two years, that the weather has been abnormally cloudy in the Fall/Winter. Is this a short-term phenomenon or is it to become a long-term pattern now that Toronto has reached over 4 million people? I'm not sure how to find this information, but I am thinking about moving, considering I have Seasonal Affective Dissorder (SAD).

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The answer

Norman Donaldson answered on January 24, 2002

Two years is much too short a period to draw any conclusions. Year-to-year variablility in cloud and precipitation is very large. It certainly has not struck me as having been particularly cloudy. Toronto is usually cloudy and grey in the fall. My book on climate of Canada says the long term average is 85 hours of bright sunshine in November, compared to 281 in July.

We did have a couple of very hazy/polluted summers, but that is different from cloud. Clouds, for the most part, are a very large-scale thing and Toronto is too small to have a huge effect by itself; some effect definitely, but not huge. If there is a change and if it is man-made, it is more likely due to the overall efffect of all North American cities. Hiding in a small town somewhere else in Ontario won't help much.

Cloudiness is connected in many complicated ways to temperature, and we have had a series of record warm years, so it would not surprise me if the last two years were different in terms of clouds. This is my own opinion, it DOES NOT represent in any way the position of Environment Canada. I have not researched this matter formally. If there was a mandate for the research we have climate experts who could do a proper assessment. However, at this time, there is no funding or mandate for such a study.

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