Another moist morning with patchy fog; but, it will burn off and allow us to reach the middle 60s today. Skies will clear completely later this evening, as a small shot of cooler, drier air infiltrates our area for a day.
Today
Murky but Mild. There will be varied temperatures throughout the day today depending on fog and scattered clouds--but mid-60s are not out of the question, especially DC & south. Broken clouds won't dissipate completely until this evening when, too, you will notice a more substantial breeze. There's no need for an umbrella or rain jacket today; just a warm top-layer to prepare you for noticeable cool-down after sunset.
Lincoln Memorial Draperies

Thursday morning photograph of eerily shrouded Lincoln Memorial [Kevin Ambrose]
Tonight, drier air moves in and cools us down with a noticeable breeze. Expect a low of 41 downtown, slightly cooler outside the Beltway, with clear skies all over (should there be a repeat of last night's Aurora Borealis).
Saturday
Closer to Reality. 54 degrees under blue skies; you can ignore a chilly breeze, right? It won't be persistent. Promise. However, the drier air will be a noticeable change from our semi-muggy air mass (at least for December!). Get that hand & face lotion back out, in case of dry patches.
Sunday
Mildness Returns. After a start in the mid-to-upper 30s, we will begin a march up to 62 degrees; Perhaps 66 in the typically warmer spots. There will be, yet again, a diurnal breeze--especially during the midday hours. But skies will be generally clear at least through the mid-afternoon.