Environment Canada says daytime temperatures this month are hovering between 7 C and 10 C, well below the seasonal average high of 21 C.
Environment Canada meteorologist Geoff Coulson said the trend is significant because of its length.
“I think what’s noteworthy about the trend we’re experiencing right now is that the cooler temperatures are happening in the second half of May,” Coulson said. “We can see days like that every once in a while later in May, but it is somewhat unusual to see this many days, almost from now until the end of the month that are cooler.”
The cold temperatures have done more than create inconvenience; a couple of nights of near-freezing have raised concerns over frost.
Environment 
Canada issued frost warnings early in this week along portions of southwestern Ontario, including the London area. The nighttime temperatures dipped to near 0 C Monday and Tuesday, creating frost conditions that were hazardous for gardens and crop farming.
It is not unusual for frost to occur in early May, but frost that persists into the third week of the month is rare.
Forecasters see the weather starting to warm back up starting Saturday, but temperatures will still be below normal for the remainder of May.
