"The Chiefs have had their Latitude 36 Bermuda grass growing ever since replacing the old-school Astroturf in 1994. It can be a tricky endeavor to keep the Bermuda going strong in the winter, but Kansas City has successfully balanced cold weather and warm-weather grass while staying all natural for the last 20-plus years."
from 2015 -
https://www.si.com/nfl/2015/09/29/nfl-stadium-turf-grass-rankings#