Ex Virus heat regulation, lifespan

“they’re cold. It seems an active process of the infection is to lower a body’s core temperature down into the fifties after death. This helps slow the decay rate even further.”
“So,” Stealth said, “can you estimate how long they last?”
“Off everything we’ve seen so far, I’m going to say the average ex can exist for twenty-eight months before decay progresses to a point where it can no longer remain active. Give or take two months, and not counting outside influences. Farther north, with seasonal changes, one could exist for four or five years. In the tropics, with the constant heat and humidity, a few months less. That cold snap we had back in February probably added a few weeks to all their lives here.”

Excerpt From Ex-Heroes, pg 189
Peter Clines
https://books.apple.com/us/book/ex-heroes/id585738407