Chicago is typically 6 hours behind Dublin. When it's 4:00 PM in Dublin, it's 10:00 AM in Chicago. Both cities observe daylight saving time, though the transition dates differ slightly.
During the brief periods when the US and Ireland change clocks on different weekends (usually in March and November), the difference can temporarily be 5 or 7 hours. For most of the year, it's a consistent 6-hour difference.
Optimal meeting window: 7:00 AM - 11:00 AM Chicago time (1:00 PM - 5:00 PM Dublin). This catches afternoon business hours in Dublin while being morning in Chicago.
Chicago has a large Irish-American community and many business ties to Ireland's tech hub.