For you guys, that have just got yourself a Raspberry Pi.
Here is a link to a project to make a weather station, using a Pi. http://www.instructables.com/id/Complete-DIY-Raspberry-Pi-Weather-Station-with-Sof/
There are many Google search result websites, that cover making a weather station using a RPi. The above link, looks to be a very good website, to guide you through the process. The guy actually makes the various wind speed and direction gauge and rain gauge, from scratch.
Most other web sites, makes use of buying the above gauges from manufacturers.
This might be a good PLUG project for a few guys, to get together and each build a weather station?
Also for anyone with an interest in the Arduino board. There are numerous web sites for building a weather station, using an Arduino board.