This workflow is a "base" for building workflows that react to weather. It uses the HERE Weather API to get weather information. HERE has a generous free tier and you'll need your own key to use the workflow (sign up at developer.here.com). After configuring your key, you will then provide a zipcode for weather information.
The second step of the workflow is where you configure your condition. It supports doing something if:
If your condition fails for any reason, the workflow ends with a message. To build a "real" workflow, you would then add additional steps after the initial one. As stated, these steps will only run if the condition you desire is true.