I removed my private OpenWeather API key from the repo, if you want to get the weather forecast use your own in the openweather_api.dart file (more info at https://openweathermap.org/appid).
I started from scatch with Flutter and Dart two weeks ago (2018/02/02), a refactoring is needed due to the ugliness of the current code since my main purpose is/was to learn them at first.
The idea behind this weather application (currently only the login page) is to learn how to use Canvas and Animation in Flutter.
It all started from an inspirational mockup two days ago, and here's the current result:
The background has been entirely coded (see header_painter.dart) except for the deer image, which has been temporarily appended using the Stack widget rather than painting it.
Enjoy it!