I don't know about you but I was not a big fan of this summer's weather patterns. Lots of rain, storms, not as much sun, etc. I was interested to know how this summer compared to past summer's, so I naturally hopped onto Weather.gov to find some historical maps (numbers are cool and all but they are harder to interpret).
Rain
The first piece of data that interested me was how precipitation has changed over the years. Once you look at the maps below, it actually appears that this summer has had less rain than last summer. In fact, it seems like every other year there seems to be crazy amounts of precipitation.
June 2005

June 2006

June 2007

June 2008

June 2009
So, what it appears (at least for June) is that this year is less than last year in terms of rain but 2006 was by far the least amount of rain.
The rain, however, isn't what gets at me so much as the lack of sun. What kind of maps can we find relating to cloud cover?
Cloudiness
Unfortunately I could not find any historical radar data or maps relating to cloud cover. However, using the daily weather observations for the Twin Cities, I was able to get monthly weather reports and in them there is a section that specifies how many days were clear, partly cloudy, and cloudy.
I put the 3-month data for years 2006-2009 into Excel and generated some simple line charts.

Thoughts
What kind of things can we see here? Well, there seems to be a common trend of usually more clear skies in July, however we can see that this summer is an exception with a particular low number of clear skies (the purple bar in the last chart). An interesting observation is also that this July has had the most partly cloudy skies compared to previous summers.
Last July saw zero cloudy skies which was the lowest compared to July 2007 which had the most.
The last chart makes it very apparent that this summer is a bit lacking in sunshiny days (during July and August). What a bummer! Hopefully next summer will be a bit more friendly.