Is it normal for heat to work only in certain hours?

Where are you? If everyone else has some heat and you live in an area where heat in the winter is a given, it is not legal for the landlord to cut off the heat. How does he know who’s at home and who isn’t? “Most people” certainly isn’t “everyone.”

Check your lease; talk to your neighbors;

@gailcalled I live in Manhattan. Right? It sounds absolutely ridiculous to me. He is this 25 year old man who doesn’t care about anything.

His age is irrelevant. Land lords have legal responsibilities, among which is not turning their tenants into frosticles.

Landlord-tenants rights, NYC

Your rights as a tenant; NYC

Heating season laws in NYC

Finding these resources took me five minutes, and I am not even lying in bed.

No it is not normal.

I have set-back thermostats.in my house. 2 zones. The bedrooms are warmer from 5:30 am to 7:30 am when it is time to get up and get dressed. It gets warm again from 7 to 10 pm. the rest of the house is on a different schedule. It comes up around 7 am and gives a little extra during meal times. At night it drops way down.

Good advice from @gailcalled. If you are paying rent, you are entitled to heat. Look at the references she quoted.

Does the landlord pay for electricity? If, yes, then get a couple of $20 electric space heaters. They work wonders.

Not OK. Check the landlord-tenant laws in your state. There is probably an agency that deals with this kind of stuff.