I posted a string related to weather info a few months back. As far as I know, there is no free-use weather polling. Weather dot com, the NOAA, yahoo, none of them will really tolerate the kind of hits weather software require.
I dunno about hoverweather, but a lot of news/weather polling software updates every three minutes by default. That is 20 hits per hour, per user. If 5,000 people use your software, that is 100,000 hits per hour. 2 and a half million hits a day that never even visits your site. Even when you give people the option of changing how often they update, most crank it back down to minute-by-minute.
If they offered a tiny xml file with the current info, like RSS, it would be one thing, but most software has to grab the entire webpage and parse out the info. I just checked the weather dot come page and it returned 52k worth of plain html, no images. That would be a lot of transfer given the numbers above.
I don't foresee any weather program being viable unless they pay for the information. There was a lot I was gonna do with scripting in that regard, but there wasn't much point.