[URBAN NOTE] On the record-breaking heat in Toronto this August

[rfmcdonald]

blogTO had a brief note, linking to the CityNews report.

[I]t was the second-hottest summer on record in the GTA and the hottest August on record.

“So far we’ve had 36 days over 30 degrees,” 680 NEWS and CityNews meteorologist Natsaha Ramsahai said on Wednesday.

The record for the highest number of 30 C days or more was 44 days set in 1959.

August was the warmest one on record with a mean temperature of 24.4 C, beating the previous record of 23.8 C in 1959.

It also was the sixth-driest summer on record, as measured at Pearson, with 113 millimetres of rain for June, July and August.

John-Michael Schneider's National Post article went into more detail.

For passengers riding on Toronto’s subways, the combination of unbearable heat and no air-conditioning on roughly one quarter of trains made travel sticky and uncomfortable. Toronto Mayor John Tory recently accepted a Twitter challenge to ride on one of the TTC’s trains sans air-conditioning. Sweltering commuters endured temperatures as high as 34C in some subway cars.

GO Transit had to slow down its trains throughout the summer, adding delay times to their schedules. The change was a safety precaution, as areas on train tracks can bend and buckle under the extreme heat, and increase the risk of derailment for fast-moving trains.

The record temperatures in Ontario can also have significant health costs. A Health Canada study of five large Canadian cities found that high temperatures during June, July and August are correlated with increased deaths. One large-scale U.S. study of over 850,000 people in California found that a roughly six-degree increase in average temperatures corresponded to a 3.5 per cent increase in strokes, a 2 percent increase in all respiratory diseases, a 3.7 per cent increase in pneumonia, and a 10.8 per cent increase in dehydration.

Heat impacts on health are worse when high temperatures continue throughout the day and night. For nearly one quarter of all people in Ontario who do not have an air-conditioning system, warm nights are a barrier to finding relief from daytime heat. Households making less than $20,000 a year are the least likely to have access to cool space.

On especially warm days, cities like Toronto can become “urban heat islands” — places where air temperatures are a few degrees higher than surrounding areas. Urbanized areas tend to be built from dark, non-reflective materials that absorb radiation from the sun and gradually release the additional heat.