Luigi, If you can, check on the average LAST killing frost of Springtime in the Chicago area and then add about 10-15 days to that to let those tender fig trees out for good .It is best to err on the cautious side. Be ready to snatch them back to a safer, warmer place if temps go below low 40's at night. Shade at first to acclimate them to outside sun and gradually move to a little more sun each day. It will make one sad to see cold damaged leaves shrivel & fall or see a promising breba fig lying in the pot or nearby. You and your figs enjoy the warm weather now, but be prepared for some more cold blustry weather. This is my experienced opinion from the sunny mid south.