How Long Does It Take for Water to Freeze?

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The time it takes for water to freeze varies from several hours to a month, depending on the volume of water, its temperature and the temperature of the surrounding air. Water freezes when it reaches 32 degrees Fahrenheit, but the time it takes for liquid particles to reach that point differs. Large lakes and deep ponds, for instance, may take several weeks to reach a freezing point and turn to solids, while a glass filled with water may freeze overnight if left outside.

The rate of water freezing varies depending on length of exposure time to frigid temperatures, but is not generally affected by surrounding container materials. When two glasses made of plastic and glass are filled with equal amounts of water and placed in the freezer for the same period of time, the water contained within freezes at an equal rate. However, temperature differences between the water in both glasses will affect their freezing rates. Cold water, as might be expected, freezes much more rapidly than hot water. Even if two glasses are filled to equal levels, the one with cold water will turn to ice hours before its warmer counterpart; this is explained by the movement of water molecules, which slows to a crawl as water hardens and solidifies.