I’m installing separate ~1.5 inch hygrometer and temperature analog gauges in a woodworking project. They’ll be recessed in the wood, should I drill a hole through the board to allow air flow to the units? : meteorology

Depends if you want it to work or look good. For accurate reading it should be well ventilated, Think the white wooden enclosures for old school weather stations.

However, analogue thermometers and hygrometer are usually quite bad, so you won’t gain too much from a perfect enclosure.