Snowflake. Light micrograph of a needle snowflake. Snowflakes are symmetrical ice crystals that form inside clouds when water vapour condenses directly into ice. The exact shape of each snowflake depends on local climatic conditions within the precise area of the cloud where it is formed. As such, no two snowflakes are identical, with each individual pattern emerging as the crystal grows. Needles are slender, columnar ice crystals that grow when the temperature is around -5 Celsius.