I triedtriefound many different weather forecast app, but I found Windy the most professional and accurate!
Anyway I think Meteogram for the app and the widgets might improved the temperature visualizzation:
In the widgets it is indicated only the maximum temperature for each day and the user has to scroll the full hours of the day to found the minimum temperature. Also the daily temperature diagram doesn't have a grid...
In my opinion adding the the minimum temperature for each day and a simple grid on temperature diagram can help the user to understand at the first sight how the min/max temperature is changing during the week.