Wednesday, 2pm CT—Anyone who walked outside on Tuesday evening—and it sure did feel almost spiritual to see the sun, didn’t it?—surely also felt the comfortable temperatures outside. It was, in fact, amazingly cool during the height of Harvey. High temperatures on Sunday (77 degrees), Monday (74) and Tuesday (75) were uncharacteristic to say the least. They were, in fact, record setting.
I checked in with Brian Brettschneider (@climatologist49 on Twitter, and a fun follow), and he came up with the following table. In it, we can see that Monday’s high temperature tied August 25, 1966 as the coolest day in the entire month of August, in Houston, in more than 120 years of records. Tuesday’s high tied for third.

Brian believes the 1966 high temperature of 74 degrees was caused by an early cold front, with lower dewpoints, cloud cover, and an overcast day. This Monday’s cooler temperatures were, of course, caused by Harvey, which by that point was drawing northerly winds into Houston, and along with cooler air, this somewhat drier northerly air also allowed for evaporative cooling as the rains fell. This was the only nice thing about Harvey.