2001 sentra hot/cold gauge keeps going up 3/4 way. is this normal

Stephen, There are a variety of things that can be answers to you question. I will do my best to address the possibilities causing the operational temperature question. I venture to guess that your question has been posed when the weather has already cooled down and you are not in a desert climate fighting close to 100 degree Fahrenheit temps and you are running the A/C? . Are you having to add coolant frequently? Nissan had a TSB out on radiator cap problems.which would cause a loss of coolant, however if the radiator is full operating temp should be in the middle until it drops low enough to just be close to the top of the down tubes of the radiator core..If you are loosing coolant other potential problem areas could be a leaking head gasket, coolant hoses or leaking heater core. Again until the coolant level drops low enough in the radiator, the temp should remain near the middle.The cooling system can be pressure tested by nearly any competent auto shops and some auto parts stores will check them for free as well as test your radiator cap.
Does the operating temp drop when you are at highway speeds or stay the same? At highway speeds, you do not need the fan to cool the engine. The ECM (Electronic Control Module) controls the fan which has two speeds and your car also has a speed sensor .
The thermostat could be another possibility where it may no longer be opening fully and will cause this symptom. It will not allow enough coolant to flow through the engine no matter whether you are at slow speeds or at highway speeds. If it runs cooler at highway speeds, you have a problem with the fan operation.
Are you operating the A/C all the time? Turn off the A/C and put your climate controls to he full heat position and see if there is a drop in temp. Your heater will act like a secondary radiator helping dissipate some of the engine heat which will cause the temp to drop. The fan on your radiator may not be turning fast enough to pull air through the radiator to drop the coolant temp. This might indicate a failing fan motor. But only if the temp drops to the middle at highway speeds. There are two fan relays which operate the fan. If you run the A/C all the time and the second relay has failed, even though the ECM has signaled the relay to operate, it will not allow the fan to increase to the higher speed. The test I mentioned of running the heater on full heat with the A/C off and the temp dropping may indicate a radiator may have trash caught up in the fins or something blocking the air flow. Don't forget that the air must pass through the A/C condenser before it gets to the radiator so if there is a restriction at the condenser it will have an effect on the operating temp as well. The radiator is a down flow type which means that the coolant enters the radiator and is suppose to pass down through every tube in the radiator and then pass over to the coolant outlet at the base of the radiator. If it is restricted, the center of the radiator is usually where the problem occurs. This can be checked by feeling the outer sides of the radiator fins going in about 5 or 6 " and then see if you can feel the center of the radiator fins. The temp should be roughly the same. If not, this would indicate a dirty or restricted radiator which will not allow it to dissipate the engine heat.Again, the test I mentioned with the heater would also point towards a dirty radiator.There is also a coolant temperature sensor. This signals the temp gauge as to what the coolant temp is. It sends a resistance value to the gauge which will make the gauge move. If the connection is corroded where it plugs in and/or the sensor is not contacting cleanly to the cylinder head it can give a false reading. If this symptom just occurred all of a sudden and you are not experiencing some of the above described issues, my best guess would be a pending thermostat failure. If you replace it, make sure you don't buy a cheap one. Your best bet is get one from a dealer. It should have an "o" ring with it which is a seal. However, Nissan also recommends using a "light " coat of RTV silicon as well. Special note. Look closely at the thermostat. There should be what is called a "jiggle valve" This is a part which has had a hole drilled through the thermostat housing and a part inserted into it which protrudes out both sides. This is designed to allow the coolant to pass through eliminating to potential for air to get trapped in the cooling system. Make sure it is installed with the jiggle valve at the top or 12 o'clock position! Some cars even have a bleeder valve which you open after filling the system and make sure coolant is flowing out of the bleeder and no air is coming out. After installing the thermostat, make sure you allow the engine to get to operating temp and the the fan cycles (it runs for a while and if you look at the temp gauge it will rise a little above the middle and when the fan runs it will drop back down.).Do some of of the tests I have mentioned and rule out the ones which do not apply toy your question. I try to spend as much time as I can to cover as many bases as I can unless you are very specific about your problem and I do not need much more input to take an educated guess as to the solution to your problem. Sorry about the lengthy explanations. Note : DO NOT JUST START THROWING PARTS AT THE PROBLEM TO SOLVE IT. i HAVE HAD CUSTOMERS COME INTO MY SHOP THAT HAVE SPENT AS MUCH AS A THOUSAND DOLLARS ON A PROBLEM AND THE SOLUTION REQUIRED NO PARTS, JUST CLEANING A DIRTY GROUND WIRE WHICH WAS ALSO NOT PROPERLY SECURED CAUSING THE FUEL INJECTION TO BARELY OPERATE. THE TOTAL COST FOR THE REPAIR WAS $45.00. THE CUSTOMER, ALTHOUGH HE WAS GRATEFUL THAT I HAD SOLVED HIS PROBLEM, WAS ALSO VERY ANGRY AT ME BECAUSE HE HAD TRIED TO PLAY "JOE MECHANIC" AND FIX THE CAR ON HIS OWN!, CONSEQUENTLY SPENT A FORTUNE ON PARTS AND GOD KNOWS HOW MANY HOURS PULLING HIS HAIR OUT. It's unfortunate he never returned as a customer, I guess because he was so embarrassed that his pride got in the way of his common sense.
Getting back to you (sorry for getting side tracked). There are some situations where it might be cheaper to pay a professional to diagnose the problem and then if it is a repair not over your head, you can do it to save money. The first person who is also a Nissan Master tech answered your questions taking a few educated guesses. The thermostat being the best one.
Ii felt I would give you more of an education as to the variables and how to look at them as well as other people reading my answer to you who may have a similar problem but the solution may be through a test or tests I suggested to isolate a problem. I wish you the best of luck, Sincerely, Bill Hackett.

Not unless the air temp is high. Could be a sticky thermostat, low coolant in the radiator, or air flow problems with the radiator.
Also a leaking head gasket.