Coolant temperature rises after exiting freeway?

[67428GT500]

I have been doing primarily street driving. I have started doing short freeway runs. Being it turns 3500 at 70, I haven't taken it on a long trip. 
I have been noting that when I come off the freeway and hit a few lights that the temperature starts running about 20% higher on the gauge for about 20 minutes post exiting. Is there a reason for this?
                                                                      -Keith

[jmlay]

Less airflow due to slower speed. When stopped the coolant flow is less as well as lower airflow.

[67428GT500]

Yes, I agree. However, if I stay on the street it stays about the same regardless. It's just after I make a run on the highway where I am running at 3200-3500 and get off it comes up and stays that way for 20 minutes or so post.

[68fecyclone]

Do you know what the oil temp is, I would bet it gets pretty warm. When you slow down the cooling system is soaking up that heat. Just a gues on my part. Rob