What can affect the strength of a hydrogen bond?

Hydrogen bonding is not a true bond. It is an attraction between molecules of a substance. Polar molecules are attracted to each other through normal dipole forces. Hydrogen bonds are stronger dipole forces due to the fact that hydrogen has only 1 electron and when that is pulled toward a very electronegative atom in a normal covalent bond, it leaves a positively charged nucleus with no other electrons around it. Hydrogen bonding only occurs between molecules that have hydrogen bonded to N, O, F. F is most electronegative so it has the strongest pull on hydrogen's one electron creating a polar molecule with F being the negative end and H, the positive. Then the opposite ends of adjacent molecules attract each other. Also, the more Hydrogen there are bonded to central atom will impact the intermolecular attraction. For example, primary amines(C-NH2) have higher b.p. with 2 H bonded to N than secondary amines(C-NH-C) with only 1 H bonded to N , which have higher b.p. than tertiary amines(C-NC-C) which have no hydrogen bonding between molecules. As far as temperature is concerned, it doesn't effect hydrogen bonding any differently than normal dipole forces. As molecules have more energy, they move more and will have less interaction with adjacent molecules eventually becoming vapor when distances between molecules are so great there is virtually no attractive force between them.