Accurate weather history

My personal story led to our developing our app. I told my software partner that I wish I could find last years exact weather for the location of my families vacation in the current year. He said "find the data" and I'll think about it.... well, a year later our iPhone app Weather Time Machine was born. I finally used it this year to say no to a trip to Boulder, CO(I've never been) in August. The weather of the past two years for our dates looked unbearable so we have made alternate plans... numbers don't lie.
So, Weather Time Machine goes back to 1960 for over 40,000 US and Canadian locations plus a two year collated data look ahead. I am no Luddite but I needed something simple. I call something elegant when things can be made simple. Our app is elegant.
As a final side story, we are looking to find a way to market our app but find its lost in the sea of apps that are floating past everyone these days. If you come up with a suggestion we use we will send you a Weather Time Machine iPhone app t-shirt. Really... no kidding. No idea is too far out. Next, we will be releasing data for international locations. Hoping to hear from you.
Mak