As Steven said you will need measurements for several years to get a good feel for the wind potential but for small set-ups you can probably manage with local data from wind surveys and airfields combined with a lot of common sense.
If a local airfield has very low wind potential and you are at a worse site then it doesn't make much sense to continue.
If the local areas have a reasonable average wind speed then you are in with a chance. You can easily see if there are local circumstances that will make things fail, trees upwind of the prevailing direction will cause you lots of problems unless you can get at least 30ft above them. Obstructions downwind are not so bad and if the prevailing direction is clear you may be ok.
There are wind maps for most areas and these can be reasonably accurate if your site is typical. If you are very high and exposed you will certainly do better. If it is low or obstructed then you may be well below the predicted figure. Someone with reasonable wind power experience could usually get a very good idea how you will compare with published data.
With small micro turbines it is probably cheaper and more accurate to install a turbine than run a wind survey. Even at the 10kW level you can with care and common sense decide whether it will pay off.
If you are going for a commercial wind farm with huge initial costs then obviously an accurate and long term survey is essential.
Most people ( not all) seem to find it obvious that you don't fit solar panels in the shade but many seem capable of locating turbines in areas where they will work badly or not at all. Just use a lot of common sense.
There will be times with no wind at any site and this may be the most difficult thing to estimate without a survey. That is a big issue if it is your only supply but for energy saving it is less of an issue. You will almost certainly find that you need wind and solar unless it is a really windy site and you can afford an over sized battery bank.
Flux