While the true weather geek will have their own weather station (though our old landlord would likely have a seizure if we tried to mount anything on the precious building), there is an alternative for those who are more commitment phobic to the science. If you're just a regular geek, Ambient Devices has a product called the Ambient Weather Beacon. Basically it's a light that changes colors based on what the weather is. The device updates automatically via a wireless radio signal and can be configured to respond to one of any number of variables including current temperature, humidity, pollen count, UV index, "feels like" temperature and others. The light will pulse (we assume gently) when there is imminent precipitation or an active weather warning.
What really intrigues Gothamist is that it can also be used for other measurements. The fact that stock market volume, and homeland security threat level indicators are available is not as interesting as public opinion tracking on topics like whether Bush will be re-elected. So if we could take it a step further (and developer tools are available), we encourage the movement towards developing indicators for things like, current availability of a cab, crowd density at one of our favorite bars, or city funk factor (especially useful in the summer).
What would you want to measure?