So, here comes my blog entry! Well, it seems like winter is not losing its grip just quite yet. We are almost into June and there is still a risk of frost in Southcentral Ontario. The main area of concern is Muskoka, Parry Sound, Grey County, and areas in higher grounds, such as Haliburton Highlands. These areas are at high risk of seeing frost developing tonight.

Yesterday, temperature soared up to the mid 20s across Ontario as a result of a push of warm air from the Great Plains of US. Today, however, a return of the arctic air cools everything down. Yesterday night, a cold front sweeps through much of Southwestern Ontario, triggering an issue with the Severe Thunderstorm Watch last night. Much of Southcentral Ontario saw rainfall amounts up to 5 mm. Behind this cold front, is arctic air from Hudson Bay. 

For everyone's information, the Hudson Bay is beginning to thaw right now, as the locale is beginning to see above 0 temperatures. In fact, nowadays for daytime high temperatures, it is extremely rare to see daytime highs of negative digits unless you are north of 75 degrees N. 

However, this airmass from the Hudson Bay area is cool enough to cool down an area that had previously witnessed mid 20 temperatures, and thus throughout today, we were seeing departing clouds, and high winds. These will be a major factor for tonight's frost.

Most of Central Ontario only hit a high of around low teens for today, and with the overnight hours, temperatures may dip as low as 0 in some locale. The clear skies and dying winds will support the formation of frost, as dew freezes into its solid form. The clear skies allow heat to be lose faster than ever. The GTA can expect temperature at around 2 to 4 C for tonight, and as we speak right now, Markham, ON is already down to 5 C. 

To the north, where the temperature is cooler and has an higher elevation, frost might be even more significant.

However, for areas closer to the Great Lakes, for example, the town of Penetanguishene, which is at the shore of Georgian Bay, the risk of frost is lower because the lake is able to "modify" the local temperature. The lakes are warmer than the nighttime lows for tonight.

Inland areas would not be as lucky, and get ready to shelter your plants (ummm... it's kind of late now, but worth a try), as frost kicks in tonight.