Thanks for reaching out to the Speakers and Displays Community forum.
A few questions: were there any changes made before? What troubleshooting steps have you tried? If you haven't already, ensure that your Assistant language is still set to English. Here are the steps: open the Google Home app > Select the Account icon at the top right > Assistant settings > Assistant language. If English is already selected, choose another language, then select English again before power cycling the unit for a minute.
You can also change your weather unit by going into your Google Home app again > Tap on the Account icon > Assistant settings > Weather > Choose Celsius as your preferred unit.
Let me know how it goes.