I turned the hot water on in the shower upstairs and only cold water came out. After about 3 minutes nothing came out from the hot water tap. The same thing happened in the sink and bathtub taps. Downstairs on the main floor I have hot water and I also have hot water in the basement.
1. Would this have anything to do with the hot water tank? The tank is not leaking and is not making any sounds.
2. Would this be a problem with my pipes? My house is 27 years old. We do not have a water softener and we do live in a hard water area.
3. The nights have been extremely cold so could that mean that the pipes upstairs are frozen?
This problem happened on Monday morning and five hours later the hot water was running properly upstairs. Now today is Friday and no hot water upstairs. It has only been three hours but we still have no hot water upstairs.
Thank you!

Apparently the hot water pipe between the upstairs bath an the downstairs bath is frozen. The pipes must be in an exterior wall. If you can figure out which wall the pipes go through you can apply more heat in that area. Otherwise increase the house temperature.