The ability to pull in weather data dynamically into the body of the ad itself is a feature that has been requested quite a bit.
Regrettably at the present time, WeatherAds does not offer the ability to dynamically pull in localized weather data into the ad copy/ ad creative itself, although you can switch ads on and off based on weather, and hence create ads that reference the conditions that are triggering them.
For instance, if you were advertising rain proof jackets, you could set up a trigger in WeatherAds to only show your ads when it was raining. Your ad copy could then say "Stay dry in the rain with our new range of raincoats. Click to order yours now"
With regards to dynamically injecting localized forecasts or real-time weather data into the ad unit itself, this feature is certainly on our radar, and we will be looking to have this functionality rolled out soon.