When the temperature of the ground is 32 degrees Fahrenheit or below, snow sticks. When the atmospheric temperature is at or below 32 degrees Fahrenheit, and there is a minimal amount of moisture in the air, snow forms. The heaviest snowfalls typically occur when temperatures hover around 15 degrees Fahrenheit.
Snowflakes are an accumulation of ice crystals formed in the atmosphere. They grow by absorbing the surrounding water droplets creating different flake formations. It can be too warm for snow to happen, but it cannot be too cold for it to snow. If the ground temperature is at 41 degrees Fahrenheit or more, the general rule is snow does not form.