You can make changes to you most parts of your AdWords or Facebook campaigns without issue. However, please refrain from changing your geo targeting settings within AdWords or Facebook for any campaigns with live weather targeting applied to them.
If you wish to edit the geo targeted locations within AdWords for a campaign which is running live in WeatherAds:
Switch off weather targeting and remove that campaign in WeatherAds
Change the geo targeting settings for that campaign within AdWords
Import that campaign back into WeatherAds and re-apply your weather targeting rules.
Most other settings can be changed for your campaign in AdWords without issue, e.g. budgets, default bid, ads, etc.