The coldest air of the season is sweeping in on gusty winds.  Later tonight with very dry air over us if the winds diminish, or the air becomes calm, some areas around DC may have some frost on the ground early Saturday morning.  The winds are the big if.  Here is the area under a frost advisory and a freeze warning. 

Frost is more likely for you folks in any low, protected spots and where there is any moisture in the ground.  Right in town DC the urban heat island should keep all neighborhoods frost free.  The high areas well to the west of DC will stay breezy but probably in some areas see the morning lows around the freezing mark. 

Some of the highest, coldest spots (you know where you are) may see morning lows in the high 20s, with a bit of a wind chill.  Here is our hyperlocal Futurecast for tomorrow morning, probably the temperatures a bit on the high side.

 Last year the first freeze in DC didn't come until December 10.  Here's a nice overview and history of the first freeze dates around the area.  One of the latest high resolution simulations shows this as morning lows in our area. 

 25° in the high spots of Frederick County Maryland  BURR!!!

Not everyone will see frost or a freeze even. If you are worried, do bring in those sensitive plants and green tomato pasta sauce tastes great too.