Switzerland. Geneva. Icicle on a public bench in the public park, Mon Repos . An icicle is a spike of ice formed when water dripping or falling from an object freezes. Typically, icicles will form when ice or snow is melted by either sunlight or some other heat source, and the resulting melted water runs off into an area where the ambient temperature is below the freezing point of water (0 °C/32 °F), causing the water to refreeze. Over time continued water runoff will cause the icicle to grow. 31.12.10 © 2010 Didier Ruef..