Entering the warmest time of the year

KMSP - Congratulations snow haters, you’ve made it to summer and what is typically the warmest time of the year.  While meteorological summer starts June 1, and astronomical summer starts around June 21, we don’t typically get our warmest stretch of weather until July… roughly 6 months or so after our coolest stretch of weather on average.  But depending on your location across the state will depend on exactly when that warmest temperature will occur and what it will be. 

Amazingly enough, for parts of western and southwestern Minnesota, the warmest temperature on average has already occurred.  This year might not be any different, with parts of the west already topping 100° so far this year.  But for the rest of the state, the warmest weather is likely yet to come.  For the metro and the rest of the southern three quarters of the state, the warmest temperature is usually anywhere from Independence Day to about the middle of the month.  But it’s a bit different in northern Minnesota mostly because there’s far more water, which moderates temperatures.  This usually prevents Cabin Country from getting to their warmest temps until the latter half of the month.

Nationwide though, it can be very sporadic and seem somewhat random, but it all has to do with overall daylight, wind direction, and the influence of moisture.  Take southern Minnesota and northwest Iowa for example.  Early in the summer season, dry southwest winds can often overtake the area which scours out moisture, combined with peak daylight, temperatures can soar.  There is a similar effect in the Desert Southwest before Monsoon season kicks in, which pushes moisture levels higher, and therefore actual air temperature drops.  For Alaska, it’s just sheer daylight hours that drive peak temps and lack of cloud cover this time of year in southeast Canada that give them their warmest temps.  For the southeast, it’s the insolation factor that builds the heat as the continued pounding of the high sun angle, southerly winds, and a lack of cold fronts passing through from the north that slowly drives temperatures to their peak levels by early August.  And then there’s the weird red shaded area right along the Pacific Ocean from southern California to northern Oregon.  Peak temperatures in these locations are much later than most of North America, coming after August 8th.  In fact, many of these spots don’t see their warmest numbers until September, when dry easterly winds funnel down the mountains and onto the coast.  This funnel effect is called down sloping, which allows temperatures to warm very quickly as they descend out of the mountains.  You have likely heard of this effect before… it is widely known as the Santa Ana winds.