I must confess I didn't expect the number of curt "the search is inadequate" responses; I posted this because it solved a particular problem I've been curious about for some time, and does a great job of displaying the data in a way that's useful to me. I found the graph display quite handy--using the same scaling on all pages allows me to easily compare different locations in different browser tabs, but the data is displayed simply enough that I'm not overwhelmed with sparklines like I am at other climate sites.
That said, I'd love to see more details about the underlying dataset; given the way the search works it appears to be a SQL database, so I assume it's public data from somewhere?
I put this site together, glad it's useful for you. The graphs are my take on climatographs.
The data is from the National Oceanic and Atmospheric Administration National Climatic Data Center, see http://www.ncdc.noaa.gov/. The dataset has good coverage of the US, but as people have pointed out, there are gaps in many places, such as the UK. The comparison is based on the monthly average max and min temperatures.
That said, I'd love to see more details about the underlying dataset; given the way the search works it appears to be a SQL database, so I assume it's public data from somewhere?