Weather Blog

Move over Seattle, Chicago aims to take "Rain City" title

Move over Seattle, Chicago aims to take "Rain City" title

Imagine the wettest of the wet days you've ever seen in Seattle -- then multiply it by, oh, a gazillion.

That might get you close to being able to fathom what happened in Chicago early Saturday morning.

A massive line of thunderstorms rolled through the Windy City, dumping more rain in a few hours than Seattle will usually see in all of November.

How much rain? In the three hour period between 12:51 a.m. and 3:51 a.m., the airport received 6.78 inches of rain -- read that again: in three hours!!!

6.78 inches is about what Seattle could expect to see in all of November and the first week of December. It's about what Phoenix gets in an entire year!

Seattle wettest day in history is 5.02" set in October, 2003. That's over 24 hours, and that was pretty much a non-stop rain-a-thon.

Let's dissect those three hours:

0.88" in one 16-minute period.
1.43" in one 19-minute period.
1.08" in one 20-minute period.
0.28" in one 3-minute period.

Breaking it down by hour, they had 2.34" between 1-2 a.m. and another 3.19" between 2 and 3 a.m., topped off by 1.25" between 3 and 4 a.m.

And then for good measure, the storm dropped another 0.12" in the hour since. In all, that storm brought 6.91" of rain -- which came on the heels of another very wet thunderstorm Friday evening that brought 1.29" in just over two hours.

According to the Chicago office of the National Weather Service, the 6.86" that fell on July 23rd (yes, not 6.91" because climate is on standard time so they don't start counting until 1 a.m. CDT and they had 0.05" between 12:51am and 1 a.m.) broke the record for wettest calendar day in Chicago's long history (which was 6.64" set in 2008.)

But the 8.20" between the two thunderstorms left the city just short of the 24-hour rainfall record which was, amazingly, 9.35" -- about 1/4th of Seattle's annual rainfall average.

The heavy rain has also spun around what was up to this point a very dry month for them. They had just 0.45" which was quite a bit below normal. Now they're at the third-wettest July on record and with a week left, could easily make it the wettest July on record.

Here are some YouTube videos of the storm, in case you ever wondered what 6" of rain in 3 hours looks like: