Which way the wind blows.
When we think about the temperatures an area gets it usually depends on where the winds are blowing in from. That means if we consider the "source region" of the air coming our way we can make a pretty good guess as to it's temperature. Generally, a wind coming from the south is warmer and a wind coming from the north is colder. That truth can be amplified by snow on the ground. Monday we had highs only in the 30s. We had winds coming from the northwest that had blown over the fresh snow pack from the weekend that tallied up to 15 to 30 inches deep from the Dakotas to Minnesota. Snow on the ground is nothing more than ice and as surface air is blown over it that air begins to cool to the temperature of the snow. No matter what direction a snow pack lies in relation to the Quad Cities, anytime the wind blows over it before it arrives here, it will always be colder than it normally would be if it had blown over bare ground! The only exception might be if that air blew over a lot of bare ground BEFORE reaching the Quad Cities. Then it might have time to modify, a bit. Or, warm-up!