Because the information is really expensive, i tried to buy data off the Met Office before it's ridiculously expensive. One month of past climate data is like £150.
I really could have used this data in my dissertation, sadly i didn't know about it then!
Good find though.
EDIT: Speaking of information, there's loads of weather stations missing. At least where i live anyway. I live in Belfast, it says the only stations are Belfast Harbour and Aldergrove Airport.
My university is in Belfast and we have our own weather station, it's data is not displayed. Also there are a number of historic weather stations who do not appear. The station here is pretty cool, it's literally live to the second on the current conditions:
http://www.qub.ac.uk/schools/gap/Research/GAPWeatherStation/ -> live weather feed.
But for general use and a weather check from your phone... yeah pretty good :p