CHICAGO (CBS) — A very chilly weekend is ahead for Chicago, and the National Weather Service has issued a freeze warning for Friday night, as temperatures could drop into the 20s across much of the area.

The entire Chicago area will be under a freeze warning from 11 p.m. Friday until 9 a.m. Saturday. Any plants left outdoors could be killed if not protected from the cold.

Daytime temperatures were expected to be in the low to mid 50s Friday, Saturday and Sunday, about 15 degrees cooler than Thursday. Friday night’s low could reach freezing in Chicago, and the mid to upper 20s further inland.

Luckily, you shouldn’t need an umbrella to go along with your coat this weekend, as there is no rain in the forecast for the next few days. However, you might want to keep your ice scraper handy, as there might be frost on your car Saturday morning or Sunday morning.

Temperatures should return to normal next week, with highs in the mid 60s Monday through Wednesday.

Despite the chilly temperatures this weekend, CBS 2 Meteorologist Megan Glaros said the upcoming winter is expected to be milder than average, due to a strong El Niño. The weather pattern happens every few years, when Pacific Ocean water warms up near the equator, and this year’s El Niño might be the strongest on record. A strong El Niño likely will bring warmer temperatures than average for the entire winter, and drier than average conditions, so possibly less snow than usual.