When planning your renewable energy installation you'll need to have some accurate weather data to give you a starting point on how you're going to size your system. If you're planning a solar panel installation you'll want to know how many hours of good sunlight you'll get a day in your location, and, if you're planning a wind turbine installation you'll want to know the average wind speed in your area.

Calculating the energy you can expect to get from the sun is a lot easier than calculating the energy you'll get from the wind. While the sun is fairly consistent year after year the wind isn't as consistent. It's likely that you'll find that the information available for the amount of sunshine you will get will be fairly accurate but the wind speed data will be way off because the information is very localized.

I don't put any faith in the wind speed data that's been gathered for my area. The station where the wind speed data was gathered from is just over 40km away and that makes a big difference. Where I'd like to install my wind turbine is a lot closer to the mountains and it just 'feels' a lot more windy that where the weather station is gathering the data from.

I'd suggest to use your own common sense when it comes to figuring out if you'd like to put in a wind turbine. The little Sunforce 400 Watt wind turbine is probably a good start if you want to do some experimentation to see if it'd be worth your time and money to install a bigger one.

So, while I wouldn't suggest relying on any of the wind speed data - you can find a really nice tool for getting the average Solar Irradiation for your area from Energy Matters.