Oslo is 7 hours ahead of Chicago. When it's 9:00 AM in Chicago, it's 4:00 PM in Oslo. Both cities observe DST, maintaining the 7-hour difference year-round.
Chicago uses CT (Central Time) while Oslo uses CET/CEST.
Optimal window: 7:00 AM - 11:00 AM Chicago time (2:00 PM - 6:00 PM Oslo). Early morning calls from Chicago reach afternoon business hours in Oslo.
Chicago has Norwegian heritage and shipping industry connections with Oslo.