The variation of the boiling points of the hydrogen halides is in the order $\mathrm{HF}>\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}$.
What explains the higher boiling point of hydrogen fluoride?

HF forms strong intermolecular H-bonding due to high electronegativity of F. Hence, the boiling point of  HF is abnormally high.

Boiling points of other hydrogen halides gradually increase from HCl to HI due to increase in size of halogen atoms from HCl to HI which consequently increases the magnitude of van der Waals forces.