Samsung Galaxy S4 — Lollipop Lock Screen temperature-unit problem

My S4 was updated to Lollipop 5.0.1 last weekend and now the tiniest problem is giving me the greatest hassle:

The Lock Screen includes brief weather info (icon, temperature, town) but the temperature is shown in Fahrenheit whereas I always work in Centigrade. My only weather app is Met Office which still shows Centigrade.

So far I haven't discovered how to change the Lock Screen to Centigrade. Can you help?

I would be just as happy if the weather info was removed from the Lock Screen. How can I do that?

Many thanks.

Thanks, Xochitl, I didn't know temperature was in the clock app.

FYI:
I moved the standard Clock to the home screen,
entered its settings menu and changed temp to centigrade
then restarted the phone.

I've now moved the Clock away from the home screen and all is still OK.

Yes, I have restarted since moving the Clock away from the Home screen, and the temperature is still in Centigrade.