1995 Other Nissan Models Temperature guage

I have a 1995 Nissan Quest with about 111,000 miles. I have noticed for a few months that even after driving for a while the temperature guage hardly ever moves into the "normal" range. If the needle starts to move up toward the normal range, the next thing it drops back down toward the "C". I think I can only think of one time recently that the needle actually moved into the middle of the normal range and stayed there. Is this a problem? Otherwise the car runs pretty well.