Temps, Heure and Fois

There are three nouns in French, temps, heure, and fois, which are translated as 'time' in English, but each has very specific uses and nuances.

Temps 

Temps can mean either 'time' or 'weather' (in which case it is almost always accompanied by the verb faire).

j'ai  le temps!	I have time!
Quel temps fait-il à Paris ?	What's the weather like in Paris?

Temps is usually singular but may be used in the plural, especially in the following phrases:

Les temps changent ...	Times change ...
Laissez les bons temps rouler	Let the good times roll

Here are the most commonly used phrases with temps:

de temps en temps	from time to time
tout le temps	all the time
prend son temps	takes his time
bon vieux temps	good all days
de mon temps	in my days
la plupart du temps	most of the time
pendant ce temps	in the meantime

Heure 

Heure is feminine and can be used in the singular or in the plural. It is used to refer to clock time.

Tu as l'heure?	You got the time?
J'ai  l'heure.	I've got the time.
Quel le heure est-il?	What time is it?
Il  est 4 heures.	It is 4 o'clock.
C'est l'heure d'Asterix	It's time for Asterix
C'est l'heure de faire la sieste!	it's time to take a nap!

Fois 

Fois is feminine and its singular and plural forms are identical. It is used to refer to one or several instances of an event.

Il a appelé quatre fois.	He has called four times.
Cette fois, il  est déprimé.	This time, he is depressed
Il  a trois fois ton âge.	He is three times your age.
C'est la dernière fois!	It is the last time!