How often do the 90's appear this late in the season?

The late summer heat tries to hold on for another couple days with temperatures both today and Tuesday expected to rise into the low to mid 90s and heat index readings rising close to 100°.  But, just how rare is it for 90° weather to be felt this late in the season? 

On average the last 90° temperature is usually seen by the end of August.  Looking back over the past 5 years of data shows that within the first few days of September there may be one or two 90's but then temperatures typically cool after that.  The exception to this was in October 2010 when the mercury climbed to 90° on the 9th.  This makes that date the latest 90° temperature on record and also happens to be the record high for that day.  The opposite occurred back in 2009 when we reached 90° in June and didn't reach another 90° temperature until 2010!  That was a chilly year!

Thankfully, the heat doesn't stick around too long.  A reinforcing cold front Wednesday will bring more seasonable, and actually below average temperatures, by the end of the week.