To get weather data into my home automation set up I use a Applescriptable program called WeathermanX. It gets all avaialbe data including forecasts and puts them into Indigo variables. WeathermanX has the option to run a script based on certain situations, however there's I could just as easily set up a time date trigger to fire this off ever so often.

The only missing last observation time which I hope the developer will add to weatherman in the future. There is another script I use which runs at midnight that tracks the min and max temps for the last x days. I'll post that later.

[Update:] I was wrong, observation time is in the WeathermanX applescript dictionary. I've added that and set it so it creates variables for every possible data point that Weatherman allows. It also puts min/max temps in a list rather than individual days.