Gary Mishler wrote:

...snip...
High performance aircraft will normally have Pitot Ht on at all times from
take-off to touch-down, visible moisture or not.

...snip...

I assume one reason would be so that you keep the PT absolutely dry of
moisture so that it would not freeze when you climb above the Freezing
Level. Also I think you would be carrying a small amount of entrapped
air from the earth's surface (relatively warm and moist), which could
condense at the colder temperatures at altitude...

Does moisture alone screw up PT readings?