Arlington Heights police reported about 600 customers who lost power on the south side of town Sunday.
Police said the area affected was south of Central Road. They said they were first notified at 6:30 a.m. Sunday.
ComEd spokesman Bennie Currie said the utility reported about 1,600 customers affected in the northern region, which includes the area north of Chicago to the state line.
Systemwide, there were about 4,500 customers without power, in an area running from Kankakee to the Wisconsin border and Lake Michigan to Dixon.
Currie said ComEd is responding quickly to the problem.
"I can't say they are all attributed to the weather, but you can certainly say a number of them are," he said. "Some of them are still under investigation, but we do have lines down and some high wind impacting the system."