There's nothing as spectacular as a smooth gloss or satin varnish coating that enhances the wood grain and showcases its natural beauty. There are many different types of varnish products to choose from, such as spar varnish and polyurethane varnish, with different recoat times and different properties, but when it comes to applying them, there are some best practices that pertain to any varnish product.
Whether varnishing indoors or outdoors, you'll want to ensure the temperature of the air, varnish, and substrate are within the varnish manufacturer's recommended temperature and relative humidity (RH) ranges.