Do you actually want to make the sensors , or do you want to use existing commercial sensors.
You may be interested in this project.
http://wmrx00.sourceforge.net/
Its called Weather Station data Logger and it uses an Arduino with a custom shield to simulate an Oregon Weather Station Console and allows
PC monitoring of a wide range of Weather conditions.
It can measure Humidity, Temperature, wind speed & direction , UV , Rainfall,Barometric Pressure.
Ive built 2 Arduino based Weather Shields, and Im now in the process of making my own Temperature / Humidity Sensors using DHT22 sensors.