Went through the same symptoms over heating on the temp gauge myself and it got worse but not thinking irregular… Though the question was not asked. “do you often put in an average amount of coolant topping up” because that may appear to be regular maintenance but to make a long story short the rad eventually went where the core was clogged impairing flow.
I have an '87 Mazda RX7 which is always on the verge of overheating…my mechanic lets me borrow his 'what I call ‘heat gun’ but it’s just a fancy thermometer to tell the temperature of any component in the engine- if if any of the hoses carrying coolant is above 210F he says I should worry. The tool is really cool just aim the laser at something and it will tell you the temperature
On the saturn I belive there is a 2 speed cooling fan set up , you have lost slow speed , when you put the AC on the High speed kicks in , there is a resistor that the connections often go bad !! << STUMP THE CHUMPS PLEASE ON THIS ONE !!