How Long Does It Take To Cook A Prime Rib At 250 Degrees?
Cooking a prime rib at 250 degrees will take approximately 4-5 hours for a 6-8 pound roast. It is important to use a meat thermometer to ensure that the internal temperature reaches 120-125 degrees Fahrenheit for rare, 130-135 degrees Fahrenheit for medium-rare, or 140-145 degrees Fahrenheit for medium. Allow the roast to rest for 15-20 minutes before carving and serving.