Canadian weather getting weirder

TORONTO (CP) — If it seems as if the weather’s getting weirder, you’re not wrong.

An index of extreme weather in Canada compiled by the insurance industry backs that up.

“Yes, we see definite trends that can’t be explained by normal variability,” said Caterina Lindman of the Canadian Institute of Actuaries.

The institute compiles what it calls the Actuaries Climate Index, a joint effort by insurance organizations across North America. It recently released its latest quarterly update — up to spring 2017.

The index begins with a 30-year average taken from 1961 to 1990 of everyday weather conditions such as temperature, precipitation, wind speed and sea level. Thresholds are set for each of those based on the top 10 per cent of readings.

For an average month, for example, about three days would be in that 10 per cent.

Using data provided by the U.S. National Oceanic and Atmospheric Administration — one of the top American government science organizations — the index then counts how many days actually exceed that threshold. The index plots the results for every three-month period since 2016.

The method reveals a slow, gradual increase in extreme weather.

The overall Canadian index indicates that during the entire three decades between 1961 and 1990, extreme weather fell outside the range of normal variability only five times. In the last 10 years, however, that happened 12 times. Temperatures have been climbing. Across Canada, hot days have exceeded the normal number every quarter since the winter of 2015. The number of cold days hasn’t exceeded normal for nine years.