What I see is appears to be condensation under the glass/plastic meter cover and should not affect the meter operation in the short term. The "guts" of the meter, however, might rust or corrode over a longer period. Yes, even digital/electronic water flow meters have physical/mechanical parts, but the one pictured looks to be a completely mechanical model.
The condensation is probably due to a non-watertight seal between the glass cover and meter body. The only real solution is to remove the viewing glass, blow all condensation out of the meter, let it air dry for a few hours, replace the seal (DON'T reuse the old one), then close it all back up.
As already pointed out, though, the water company owns the meter and they usually do not permit customers to perform any kind of maintenance or repairs to the meters due to the potential for cheating the company. Best to contact the water company and let them decide what to do and then do it.