Improved code quality by making code dry in weather.dart

[shatanikmahanty]

Hi team, really great work with this project. I found the weather.dart file had lots of repetitive code which would cause maintainability issues in the feature and also accessing a variable multiple times causes performance issues. I made the code much more dry and promoted reusability through this PR.

[Leonavichus]

Thanks a lot for improving the code!