I live in Miami so, I haven't had to deal with frost or freezes yet. Ilama growers in Central Florida and California should have more insight on cold tolerance.
In it's native habitat, there is a long dry season from, approximately late fall to late spring. Excessive rain during the winter dormant period is very detrimental to ilama, particularly the root system. Also, If the rainy season starts too early, it can have an adverse effect on fruit quality.