There are lots of afordable temperature sensors that have outdoor sensor that transits temperature to indoor unit. You can capture this transmission and decode it with rtl_433 package and cheap DVB-T songle.
rtl_433 is package that turns your Realtek RTL2832 based DVB dongle into a 433.92MHz generic data receiver.
To install rtl_433 on Fedora 21 just follow these simple steps:
sudo dnf install cmake libusb-devel rtl-sdr-devel git clone https://github.com/merbanan/rtl_433.git cd rtl_433/ mkdir build cd build cmake ../ make cd src ./rtl_433
If you get error message then it is likely that you have module confilict. Just remove or blacklist these modules:
dvb_usb_rtl28xxu, rtl2832, rtl2830, dvb_usb_v2 and dvb_core:
sudo rmmod dvb_usb_rtl28xxu rtl2832 rtl2830 dvb_usb_v2 dvb_core