Record-Breaking Rainfall: Chicago Sees Wettest May In History

75756A5E-120A-4932-810C-2FD980DB785E

CHICAGO (WBBM NEWSRADIO) -- A little rain overnight Monday pushed Chicago over the top for another dubious distinction: no month of May has ever been wetter in the city.

With more than a week to go in the month of May, Accuweather reports that Chicago received 1,100ths of an inch Monday night into Tuesday morning pushing the total for the month of May over 8.25 inches of rainfall - edging out last year's record breaker. 

The National Weather Service also confirmed that amount stating, "the May precipitation record for Chicago has been broken with the 0.11" observed today at O'Hare through 4 a.m., pushing the monthly total to 8.30". This passes the previous record of 8.25" set just last year. This also marks three straight years of setting new May precip records."

The May precipitation record for Chicago has been broken with the 0.11" observed today at O'Hare through 4am, pushing the monthly total to 8.30". This passes the previous record of 8.25" set just last year. This also marks three straight years of setting new May precip records.

— NWS Chicago (@NWSChicago) May 19, 2020

This year marks the third consecutive year that a monthly rain record has been broken. Last year, May saw a record-setting month with 8.25 inches of rain; and in May 2018, another record was set with 8.21 inches of rain.

And even before Monday night's rain, the 7.88 inches of rain Chicago has received over the last four days alone would already be the third-wettest May on record at O’Hare, according to the National Weather Service.

Top 5 wettest Mays in Chicago:1) 2019: 8.25"2) 2018: 8.21"3) 2020: 8.20" (thru 7 am May 18th, still 13 days to go)4) 1945: 7.59"5) 1883: 7.32"The 7.88" of rain on the 14th-17th this month would have been enough to break entire monthly record prior to 2018 in just 4 days!! https://t.co/DV07DUodSQ

— NWS Chicago (@NWSChicago) May 18, 2020

Meanwhile, flood recovery continues in the Chicago area. 

The city said more than 1,600 calls poured into the 311 system, with reports of flooded basements.

Lower Wacker Drive remains closed to regular traffic, because of high water, and the basement of Willis Tower is still being emptied of water that spilled into it from the Chicago River. The flooding knocked out a ComEd substation in the basement.

ComEd will not be able to restore electricity to the building until its crews can safely get into the Willis Tower basement.

The drive-through COVID-19 testing site in Markham had to be shut down early Monday, because a section of the road leading to the site collapsed. There are plans to reopen the site Tuesday.

Even the deep tunnel reservoirs were overwhelmed with over four billion gallons of water and sewage.