Can you keep your guinea pig at 85 F?

Opinion 1:

No you need to keep them around 72 degrees.

Opinion 2:

Guinea-pigs can easily handle ranges of temperatures ranging between 20 degrees Celsius (68 degrees Fahrenheit) and 30 degrees Celsius (86 degrees Fahrenheit).

In warmer areas where the temperature exceeds 30 degrees Celsius, make sure your guinea pig's cage is always in the shade. They can certainly tolerate weeks of high daytime temperatures, as long as they have fresh water and food daily, but their natural cycle needs the night-time temperatures to drop.