Temperature is a function of the time if day.
We can say f(x)=y
So y is dependent on what the value of x is.
Same for the temperature. The time if day is not dependent upon the temperature outside. However the temperature outside is generally dependent upon the time if day.
So it’s colder in the morning as a general rule and the temperature increases as the time of day gets later then goes back down again as the time if day gets later into evening. So we can see that the time of day is independent of anything and the temperature depends on the time if day it is.
Hope this helps you. Any questions feel free to ask. Have a great day!