Some of the Elements in your Weather Template, such as Wind and Humidity, will appear in English as they are part of the template itself.
You can change these elements of your Template by Editing your Weather Widget within your Layout, select the Appearance tab and tick the Override the Template box. Below are screenshots showing how I did this:
This is how Template 13 appears when set to German:
To change the English elements, I tick the Override the Template and manually change the English to German.
After changing Humidity and Wind to the German Translation, my Template displays correctly.
Please note that the Wind Direction is set by the API itself and so cannot be changed within the Template.
Also to change the Wind Speed to KPH from MPH, whilst in the Edit Weather window, select the Advanced tab and set the Units to Canada.