PM Update: Hard freeze tonight for much of the area, then we start warming up Thursday.

'The sun’s angle — how high it gets above the horizon — was about the same today as it is in mid-January. That might explain why its rays were so futile when it came to getting temperatures to rise today. Highs mainly in the mid-40s were a good 10 degrees or more below normal for the date. A cold snap is unusual of late, and this one will be rather short-lived, but with winds dying down this evening, the stage is set for a long overnight freeze in many spots. But will downtown make it?

Through tonight: Chilly and clear conditions will be the rule. Thankfully, winds will die off significantly after sunset. They’ll become light and variable overnight. Lows will range from the mid-20s to low 30s. Most spots outside the Beltway should see temperatures fall into the 20s for several hours, although downtown may escape its first freeze of the fall, at least officially.

Tomorrow (Thursday): We’ll have another day of near 100 percent sunshine. It will turn warmer, with highs in the low and mid-50s. Winds will be from the south around 10 to 15 mph.

Another shot: While last night’s temperatures were a little milder than suspected, with most spots staying above freezing, tonight should give it another go for first freeze in many locations. It’s getting late to not have much in the way of cold. Over at Dulles International Airport, the National Weather Service says it’s the latest we’ve made it in the calendar year without dropping below 32 there.'

https://www.washingtonpost.com/weather/2020/11/18/pm-update-hard-freeze-tonight-much-area-then-we-start-warming-up-thursday/?