Fickle temp gauge in 2008 accord?

Hello,

Today I noticed that for a few hours my temp gauge in my accord decided to

stay at 59F even though the temp outside had moved from 59F to 70F. Later,

in about 3 hours the temp gauge reads the right temp of 87F. Other weather

conditions are clouds and fog that later changed to sun, but I never heard

of this happening? Any thoughts on this? Car was moving during the time
that 
temp read out was stagnant.

Thanks,
Al