UPDATE: The National Weather Service has issued a freeze watch for York County for Friday night and Saturday morning.
A cold front moving into central Pennsylvania at that time will bring temperatures in the low 30s to the lower Susquehanna Valley and temperatures into the mid-20s in the central and northern mountains, the service said.
Sensitive plants or crops could be damaged or killed, the NWS warned.
Previous story: York could see its first frost of the season Friday night.
Thursday, York will be sunny, with a high of 61 and low of 39, according to the National Weather Service. Winds will be from the northwest at 5-10 mph.
Friday will have increasing clouds, and northwest winds will pick up to 11-16 mph, the forecast said. The high will be near 60, and temperatures are expected to drop to 32 Friday night and Saturday morning, bringing widespread frost.
Saturday will be sunny, with a high of 62 and low of 44, the NWS said.
Sunday will be partly sunny and warmer, with a high of 68 and low of 53, the forecast said. There's a chance of showers Sunday night.
Monday and Tuesday will be mostly sunny, with highs around 70 and lows in the mid-40s, the service said.