ZZR250 Operating temperature question

Hi, I was just wondering if anybody can provide some opinions. I've had problems with cooling systems in the past, so I am a little paranoid, but your opinions are appreciated.

I have a zzr 250, 2003. I don't know if its the change in weather, but a week ago, the bike was running in the bottom 1/4 of the gauge at 80-90km/h, and on the hwy at 120km/h. Recently, it runs at about halfway, sometimes going up half a block, sometimes going down, even if the speed remains consistent. The fan is on a manual switch, radiator cap is new, and the coolant is at the right level. I was just wondering if this is normal, or if there is something I should look at. Thank you for any input.