Coolant temp gauge

[MegaCode360]

Started noticing this winter that my temp gauge doesn't stay right at 210.  When I press the gas to accelerate it will climb to 210, but when I let off the gas to coast, it comes down to just above the first mark before 210.  I don't know that it's done this before, it very well could've, but I'm just noticing now.  It's winter where I'm at and generally cool to cold outside.  I am still getting heat in the cab just fine.  Is this the sign of something going bad or the beginning of a problem?  Or is this normal?  Thanks!

[MegaCode360]

Bump