Chilies of all kinds really like it hot. We've had a very cool summer and I wouldn't be at all surprised if we get an early frost, so suggestions that you use your habaneros green are probably right on.
You may want to give your peppers a heat boost by putting some clear plastic around them. A good method is to put a tomato cage around the plant and then wrap it in plastic. Leave the top open for ventilation. Or you can make a tent out of plastic above the plants and leave the sides open.
Since your plants are in pots, you can stretch the season a bit. When the temperatures start to drop at night, bring the plants inside at dusk and return them to the sun in the morning.
We really don't have a long enough growing season in Chicago for most varieties of habanero-type peppers to ripen.
By the way, once the plants start to fruit, you want to cut back fertilizer; it encourages leaves at the expense of fruit.