In building WindOnTheWater.com, I found many wind data sources online.
Different datasets are available online across many websites, in a number of different formats.
Seeing data on a map is so useful that most major weather websites provide a map interface to see data.
Here are some of the weather mapping websites I am familiar with, and a quick review of each.
Screen shot and link also provided because sometimes the map view is a bit hard to find on each website.
Google map displays all the mesowest data. The interface provides alot of weather data with graphing.
Different format to get all the mesowest data
Like Mesowest, but not quite as nice an interface. Seems to be some data delays relative to Mesowest making this a bit less useful.
Nice google map interface, has nice data like satellite images, webcams, and much more. It is a bit slow for me when the extra data is turned on.
WeatherBug weather stations data and webcams, along with NOAA data. This uses Bing Maps (previously maps.live.com), instead of the popular Google maps. One nice thing about Bing Maps is the birds eye view and higher resolution aerial photographs in some areas. The weather stations are usually at schools, but some at more interesting locations. WeatherBug doesn't appear to archive weather history (but WindOnTheWater.com does archive this data for useful stations)
Another network of private weather stations. Easy to find location of stations based on google map interface.
National Data Buoy Center
Focused on buoy data, another google map interface.
Tides and Currents, PORTS
Mostly the same buoy data as above, but has some extra data stations with access to river levels, currents, etc.
CWOP/APRS is another dataset, this is an interface that shows these weather stations, but not so nice, and I think Mesowest includes all these weather stations.
SailFlow, WeatherFlow, iKitesurf, iWindsurf
Has a subscription based private network of sensors and includes public sensors.
This website. The focus is on real time wind, collecting data from public and private sources to display on a Google map. Also has alerts, wind phone, iphone pages, etc on top of this data.
Please leave a comment if you know of any websites I missed.
Like this one:
http://mapcenter.hamweather.com/interactive/ (has some webcams)