mystic84: I'm a newbie so I'll give you some detailed steps assuming you are using the RPi generic home screen
1) open file manager in the Pi MENU > ACCESSORIES > FILE MANAGER
2) paste THIS into the openbox to the right of the file icon:
/home/pi/ is the default that appears
/home/pi/.kodi/addons/weather.yahoo <---
don't forget the *.* before kodi
... just cut-paste the above sentence
3) double click on default.py icon [this will open the file in the python editor]
4) Here is how I documented the change at line 21 [you'll have to use the down-arrow and count to 21]
4a) highlight the line: API_URL = 'http://weather.yahooapis.com/forecastrss?w=%s&u=c'
4b) cut the below code, all five (5) lines
# ***************************************************************************
# API_URL = 'http://weather.yahooapis.com/forecastrss?w=%s&u=c'
# changed per post #165 at
http://forum.kodi.tv/showthread.php?tid=169410&page=11
# ***************************************************************************
API_URL = 'http://xml.weather.yahoo.com/forecastrss?w=%s&u=c'
4c) Paste clicking on Edit-Paste or keystrokes = CTRL+V
5) Click on File-Save or [CTRL+S]
6) after about 20 seconds your YAHOO weather should begin to work
If you appreciate this answer please +1 below.
Thanks.