We are in process of building out a reporting module within WeatherAds and hope to have this feature launched in the coming months. This feature will enable users to get insights into the percentage of time your ads were on or off, and the amount of time your bids were being adjusted up and down, along with insights into the effect that the weather targeting is having on your campaign's KPIs.
In the meantime, our clients typically get their reporting straight out of AdWords or Facebook, where they can get all the information they need on the performance of their weather targeted campaign(s).
For Facebook, since you are simply turning ads on and off based on weather, all of your KPIs (Impressions, CPC, CTR, Conversion rate etc) will have occurred when your ads were switched on, starting from when you set your weather targeting live.
For AdWords, you can also see a record of which geo locations were added and removed, or had their bids increased or decreased, along with a timestamp. This information can be accessed from your your campaign's change history.