Weather extremes evoke a very powerful cognitive bias we all have called hard wired into our DNA the "RECENCY EFFECT". This effect gives higher importance to events that have occurred more recently and lesser weight to events further back in time. The last three summers (2012, 2011 and 2010) have all featured some record heat. These memories are more recent in our minds so we give them more credence than a distant memory of a summer in, say the early 1990s or early 2000s.
Viewer Facebook comments all illustrate this bias perfectly. Most comment that this summer is so unusual. Most say that don't remember a summer like this in a long time. Yet summers like this one have occurred more often than most of us (myself included) realize. Best of all, we don't have to go that far back in time to find them.
Below is a chart that summarizes ALL of the summers (JUNE and JULY) over the last 30 summers COOLER than this summer. I only averaged the HIGH TEMPERATURES as most of us really don't remember nighttime lows. I listed each year from WARMEST to COOLEST.
* 19 OF THE LAST 30 SUMMERS HAVE BEEN JUST AS "COOL" OR COOLER THAN THIS SUMMER. (SEE MY LAST POST)
* 7 SUMMERS (DAYTIME TEMPS) SINCE 2000 (2000, 2001, 2003, 2004, 2006, 2007 and 2009) HAVE BEEN "COOLER" THAN 2013
* THE MAJORITY OF THESE "COOLER" SUMMERS HAD MORE DAYS IN THE 60s AND 70s THAN THIS SUMMER
* MOST OF THE "COOLER" SUMMERS SINCE 2000 ALL HAD STRETCHES OF "70 DEGREE TEMPS IN JULY" COMPARABLE TO THIS SUMMER
The moral of the story is we all perceive this summer to be so earth-shatteringly COOL. Yet even some of our more recent summers contrary to what our memories tell us have been just as cool.