Mobiles & crowdsourced weather measurement
I shared this from The Economist quite some time back: Counting raindrops. Here is an example of folk using mobile phone networks themselves for weather forecasting.
Today I stumbled upon Cumulonimbus. They have an Android application called pressureNET, which makes use of the barometer in some Android phones. This is user-contributed atmospheric pressure readings, embedded on a Google map. It is available to view at http://pressurenet.cumulonimbus.ca/.
It seems many devices have a barometer as well. Samsung leads the pack with the Galaxy S3, S4, Note, Note II, Galaxy Nexus. It also comes with the Nexus 4 & Nexus 10.