Hi jojoe,
If I understand you correctly the potted Callas have bloomed and are in leaf, not dormant corms.
If correct, wait until several weeks after your last frost date to plant out. You don't want to stress the growing plants with sudden cold and wind. Mine stay actively growing until autumn frost, months after blooming. Lack of water will force them into dormancy as well.
The main issue I see is depth. I don't know how deeply they're planted in the pots but probably pretty close to the surface. Most like to be about 8" deep in ground, so at some point after they've gone dormant, you should dig them up and re-plant at a proper depth.
