How can it rain at 26 degrees?

Dear Tom,
How can it rain at 26 degrees?
Jim O’Shea, Oak Lawn
Dear Jim,
The form in which precipitation reaches the ground is not determined by the surface
temperature, but by the temperature profile from the ground to cloud-level. Most winter
precipitation begins as snow. If it encounters a deep enough layer of above-freezing air as
it falls to Earth, it melts and becomes rain. The rain then refreezes when it makes contact
with the below-freezing ground and the result is a glaze-producing freezing rain. If the
rain falls through a thick enough layer of belowfreezing air before it hits the ground, it
refreezes into ice pellets (sleet). Forecasting winter precipitation types is difficult,
especially in the Chicago area, a region that is frequently close to the dividing line
between rain and snow.