Toronto's thirsty! City approaches record for driest July ever

After a parched, scorching month, it may turn out this was the driest July on record, forecasters say.

Observations at Pearson Airport indicate the city has seen no rain since July 3, and just 4.4 millimetres of rain in total fell in the last 4 weeks.

“That would be enough to keep the dust down and that’s it. Toronto hasn’t had a drink of water in 18 days,” said Dave Phillips, senior climatologist at Environment Canada.

The driest-ever July was in 1957, with 11.5 millimetres of precipitation. That means that the city would have to see a good 7 millimetres of rain before the end of the month, or risk breaking that bone-dry record.

What’s worse is that this heat-wave of a July, with its humidex advisories and recent extreme heat alerts, is making the need for water all the more pressing.

Although Thursday’s high, at 37 degrees, did not break the all-time record for a high temperature at Pearson, it was the hottest day of the year, the hottest July 21 on record, and the hottest day in the month of July ever recorded in Toronto.

“We’ve had less precipitation and the effects are much greater now because it’s been much hotter. A lot more days above 30, and the average temperature 2.2 degrees warmer than normal,” Phillips said.

But there could be relief in sight as Environment Canada reports a 30 per cent chance of showers early Saturday morning. Sunday might also be inclined to give us a break, with a 60 per cent chance of rain.

But that doesn’t mean you can let up on the sunscreen, as Saturday’s high is 35C and Sunday’s is 29C.

Sunday is expected to be cloudy, but Saturday will likely have a UV index of 9, or very high.

There have been 13 days in July logged at temperatures above 30. “So even if we get some rain between now and August 1, we probably would be in a worse dry situation [than 1957] come the end of the month,” he said.

Meteorologist Marie-Eve Giguere explained why summer thunderstorms are typically so common in southern Ontario.

To produce a storm, three elements are required. “You need moisture, which no doubt is in the air mass. And you need instability. So with the heat, you have an unstable air mass. You need a third thing, a trigger,” Giguere said.

Cold fronts typically provide the trigger, by pushing the warm, humid air up, creating clouds. But the minor cold front that moved in over the GTA yesterday was simply too weak to make it rain.

“It’s still pretty sultry and oppressive,” Phillips said. Friday’s high is expected to reach 35.

The weak cold front “wasn’t enough to trigger anything,” he said. The closest chance of rain is Monday, at just around 30 per cent.

Elsewhere in the province, firefighters are battling forest fires in northern Ontario that have forced thousands from their homes.

The province said 114 fires are burning over nearly 500,000 hectares of forest, mostly in the northwest.

The hot, dry conditions are making it difficult to stamp out the flames.

Zoe McKnight, Staff Reporter with files from the Canadian Press