Here is a summary of the provided text in one paragraph: To create a simple weather app with PHP and OpenWeatherMap API, start by setting up the project structure, installing required dependencies, and configuring environment variables. Next, create routes for searching and displaying weather data using Slim Framework and Twig templates. The search form route renders a search form, while the weather report route processes form submissions and retrieves weather data from OpenWeatherMap API. The application uses a custom error handler to render error pages with details of exceptions or errors that occur during execution. Finally, test the application by running it on a local server, entering city names, and verifying that it displays accurate weather information and handles errors correctly.