In order to calculate the number of degrees it warms every hour, we need to divide the total change in temperature by the change in time.
First, let's calculate the change in temperature, subtracting the final and the initial temperature:
Now, let's calculate the change in time.
The initial time is 8:00 a.m., and the final time is 1:00 p.m., between these times there are 5 hours, so the change in time is 5 hours.
Finally, calculating the number of degrees it warms every hour, we have:
Therefore the increase in temperature is 3 °F per hour.