We are now exploring the new Universal Analytics, which is a replacement for Google Analytics. It all seems to be just another update, but there is much more under the hood. You can now add a custom dimension and it can be anything, for example current weather.

How to add weather to Universal Analytics:

http://www.simoahava.com/web-development/universal-analytics-weather-custom-dimension/

It's a clever mashup of Universal Analytics, openweathermap.org and www.geoplugin.com.