Hydrogen bonds between water molecules are broken as water vaporizes, allowing individual water molecules to separate from one another. It requires a substantial amount of energy to break these bonds, giving water a much higher boiling point than it would otherwise have.
In addition to giving water a relatively high boiling point, hydrogen bonding is also responsible for water's ability to absorb large amounts of heat energy. This property of water accounts for water's moderating effect on climate. Other properties of water related to hydrogen bonding are surface tension and adherence. These properties allow water to rise in narrow tubes against the pull of gravity, a process called capillary action that is vital to the biology of plants.