I posted a slight update at the link above which allows you to ask for the weather in a wider variety of sentences.
Copy this over the old version and save it, then uncheck the weather plugin, click OK, go back into options and recheck the weather plugin. This resets Hal to include the new version. Then you should be able to use it.
If you look at it, you can see the range of phrases it checks for. You can add or change them as you see fit, as long as you leave the first two and the last line of the new section as they are. For instance, if you wanted to be able to just say "weather report" and get the response, you could simply add this line in the middle of the group:
InStr(1,OriginalSentence, "report",1) Or _
This would make Hal check each sentence for "weather" then any sentence with "weather" would also be checked for "report". If both criteria are met, Hal will respond with the weather report.
Let me know if you have any problems.