There’s a chance the Chicago area may see some snow by the end of the week.

A slight chance of snow is in the forecast overnight from Thursday to Friday, according to the National Weather Service. Current predictions put the odds at 20 to 40 percent after midnight, and it’s too early to say how much snow could fall if it happens at all.

The season’s first snowfall happened on Oct. 21, when soft, hail-like snow pellets called “graupel” fell for about 30 minutes.

It came earlier than usual, as the average first snow for the Chicago area happens on Oct. 30, according to NWS records. The earliest Chicago has seen its first traces of snow was Sept. 25, which happened in 1942 and 1948.

The average first measurable snowfall – a tenth of an inch or more – usually comes by Nov. 17, while the first snowfall of at least an inch typically happens around Dec. 7.

High temperatures are expected to linger around 50 degrees on Monday and Tuesday, before dropping into the mid-40s on Wednesday and into the low 40s or upper 30s on Thursday and Friday, according to the weather service. Overnight lows could dip into the 20s starting on Wednesday night.