The problem results from SmartThings decision to eliminate their weather API. See: Announcement: Weather API Changes
The easiest way to get the functunatility back is to switch to the Colorcast app which is based on this code, but uses a different weather API. See: ColorCast - Color Changing Weather Lamp
To install it:
- Go to http://www.smartthings.com/developers/ and create an account
- After your account is created go to “My SmartApps” then click “+ New SmartApp”
- Select the “From Code” tab
- Copy the code from https://github.com/jdiben/Smart-Weather-Lamp/blob/master/Smart-Weather-Lamp.groovy and paste it into that page
- Click “Create”
- Click “Publish” then Click “For Me”
- When that’s complete just go to the SmartThings app and add a new app
- Swipe the top section over to “My Apps” and tap the app you just created.
- Follow the onscreen setup and you’re done.
Hope this helps