Hot in the Windy City. June ends on blistering note for Chicago residents

If the rest of summer 2020 plays out anything like the month of June did, residents in Chicago are in for a sweltering season. June in the Windy City was particularly notable for the near-record number of intensely hot days.

With a high of 91 degrees Fahrenheit recorded at Chicago-O'Hare International Airport on Tuesday, June 30, the city notched its ninth 90-plus degree day of 2020 before the calendar flipped to July. According to the National Weather Service (NWS) office in Chicago, the nine-day total is the most since 2012, which saw a blistering 17 days at or above 90 F before July. On average, the city sees four 90-plus degree days through the year's first six months.

NWS Chicago meteorologist Brian Leatherwood told AccuWeather that the historical average for 90-plus degree days for Chicago is 15 per year. If the city sees another hot stretch of days like it did in the middle of June, that average should be easily surpassed.

Eight of the Windy City's nine 90-plus degree days came in June with six of those days falling between June 8 and June 20. Over that stretch, the city only picked up rain twice.

A woman attends a peaceful rally in Chicago, Friday, June 19, 2020, to mark Juneteenth, the holiday celebrating the day in 1865 that enslaved Black people in Galveston, Texas, learned they had been freed from bondage, more than two years after the Emancipation Proclamation. (AP Photo/Charles Rex Arbogast)

"What we've had is just a blocking pattern that led to most of the weather going around us for a couple of weeks and there was a lot of heat associated with also," Leatherwood said. There was no precipitation at all to speak of for a week-long stretch due to the blocking pattern, and it was during this period that temperatures soared. However, an active weather pattern set in during the past five days, and total rainfall ended up climbing above normal for the month with the city picking up 4.40 inches compared to the normal June amount of 3.45 inches.

Even though the precipitation total may not have been unusual in the rearview of the entire month, the total number of warm days certainly was.

AccuWeather Senior Weather Editor Jesse Ferrell found Chicago recorded the fourth-most 85-plus degree days in June and the first half of 2020. The nine days between Jan. 1 and June 30, on which the mercury climbed to 90 or higher, adds up to the fifth-most 90-plus degree days in Chicago's history in that six-month timeframe.

According to NWS record keeping, which dates back to 1871 in Chicago, 1954 saw the most 90-degree days in June with 16 and 1988 recorded the most 90-degree days in a year with 47. Historical averages for late June show temperatures are typically in the low- to mid-80s at this time of year.

A man runs past a closed furniture store Friday, June 5, 2020, in Chicago. The federal unemployment rate declined to 13.3 percent in May from 14.7 percent in April with a gain of 2.5 million jobs. (AP Photo/Nam Y. Huh)

The city is approaching the 25-year anniversary of its catastrophic 1995 heat wave which claimed 739 lives over a five-day period. Similar to those previously mentioned years of 1988 and 1954, along with 1995, a key spark for the June heat of 2020 was rain-related. As Leatherwood mentioned, it was really the lack of precipitation that was to blame.

Unlike Miami, which endured its own stretch of record heat to close out June, Chicago is not experiencing a resurgence of COVID-19 cases and is moving forward with Illinois' Phase Four reopening. The reopening includes allowing pools to open with certain restrictions. But, with millions in the city practicing social distancing at home, wearing masks while out in public, and so much of life's routines thrown off balance, even a short-term heat surge could feel more intense than ever before.

"It was just the fact that we had that big high pressure that was over us for a while and diverting all the storms around us," he said. "Which just led to more sunshine than normal and less precipitation than normal. It was short-lived, but it probably seemed like a long time for some people, especially when the grass turns brown."

And a peek at the AccuWeather forecast for Chicago shows that away from the lakefront, Chicagoland will have to endure a lengthy heat wave spanning the extending holiday weekend and next week.

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