I'd like to be able to compare and contrast today's weather conditions with the conditions recorded on the date one year ago. Long range forecast would be cool too.
Kinda off topic, but I once spoke with a guy who taught weather forecasting for the military. He explained that TV, cable, and radio don't hire forecasters for their skills - they hire them so that they will do OK if they are ever used in broadcast. In contrast, wars are won or lost based on weather forecasts - so the military invests like no one else in training their forecasters. He told me that if I want a decent forecast, I need to find out which government agency provides forecasts for a nation's airlines. They will be the only civilian organization investing in getting the good forecasters. (And I have found that to be true for the US - the National Weather Service (NOAA) consistently has better forecasts.) I know that this doesn't answer your question - but it seems like this isn't widely known, considering the horrible forecasts I routinely ignore from my phone, computer, and browser.