My water temp seems very high. On my Defi gauge, it is reading at 105C. Usually when the weather is in the teens, the gauge will be reading at low 90C.
These are the things I have checked already:

a) The coolant level on both the rad and reservoir bottle seems fine which indicates enough coolant in the system

b) The low rad hose after a drive is hot which indicates the thermostat has .opened.

c) The fan is kicking in at around 100C which indicates the thermswitch is working.

d) The factory water temp gauge reads 1/5 below the half point mark which seems to be normal.

Anyone know why the sudden increase in the water temp?

 

The situation:

your factory gauge that was hooked up by factory technicians and honda engineers works fine. The fan works fine, and it only comes on when needed....it's not trying to cool all the time.

Your aftermarket gauge reads too high.

The obvious answer:

It's more than likely an erroneous reading from your aftermarket gauge.