This is the script that's shipping with Indigo 4.1 (so don't download it unless you're using Indigo 3). It hasn't been tested with Indigo 3, but some users have reported that it works, so we're just providing it here.
Create a startup trigger that runs the script - it's a background script. NOTE: don't call it multiple times or embed it.
Create a variable named _Weather_Fetch_Station and give it the 4 letter code for the nearest NOAA weather center to you. The script will then populate a bunch of variables with weather data that you can use any way you want.