(CNN) As the summer solstice approaches on Saturday, soaring temperatures will bake parts of the Midwest, northern New England and eastern Canada through the weekend, potentially writing new records.
From Chicago to Quebec City, temperatures are forecast to soar above average.
It's not just the unusually high temperatures officials are concerned about. Excessive humidity will push the heat index values above 38 degrees Celsius, or 100 degrees Fahrenheit, in Canada where a heat wave is expected.
A heat index value -- known in Canada as humidex -- is what it feels like outside when you take into consideration the humidity and the actual temperature.
The summer heat will be combined with the most intense sunshine of the year as the Earth's north pole is at its maximum tilt toward the sun.
The summer solstice -- the start to summer according to the astronomical calendar -- is also the longest day in the Northern Hemisphere. This will allow for more daytime heating.
Red Alert Heat Warnings are in place for southern Manitoba and Ontario provinces, as well as New Brunswick and Nova Scotia. Meanwhile, special weather statements have been issued for Quebec.
Daytime highs are forecast to reach 33 degrees Celsius, 91 degrees Fahrenheit, for Quebec City on Friday, which will challenge the old record of 31 degrees Celsius, 88 degrees Fahrenheit, set back in 1995.
The definition of a heat wave in Canada is dependent on where you live. The country's meteorological department, known as Environment Canada, generally refers to heat waves as two or more consecutive days of temperatures at 30 degrees Celsius, 86 degrees Fahrenheit, or above.
Check if your location will reach heatwave status >>>
What makes heatwaves so unbearable across eastern Canada is that many people don't have air conditioning.
Officials are reminding residents that during times of high heat, your health or your family and neighbors' health can deteriorate rapidly.
It's essential to drink plenty of water, seek air conditioning or shaded areas when possible, and check on those most vulnerable to heat stress like the elderly or very young.
The recent temperature disparities couldn't be more apparent across the US to Canada as highs have already soared well into the 90s this year for Ottawa and Montreal.
Meanwhile, in the southern US, where you expect these temperatures this time of year, cities like Atlanta await its first 90-degree Fahrenheit reading of the summer. That's a rarity by mid-June standards, especially for a city often referred to as "hotlanta."
"Atlanta is used to temperatures in the 90s this time of year, but this is already the third latest start for the first 90 degree temperatures in the city," CNN meteorologist Michael Guy says.
States like Virginia, North Carolina, South Carolina and Georgia have been well below average this entire week.
This weather pattern responsible for bringing cooler temperatures to the southeastern US and locking in days of drenching rains across the Carolinas this week is helping force hot and humid weather northward into the St. Lawrence Valley.
The pattern isn't forecast to break until early next week as a cold front advances eastward.