Cold night and north wind: Expect low humidity and cold snow. Wax for colder than expected conditions
Overcast: The snow will be closer to the air temperature and more humid. Wax for warmer conditions with higher humidity and more structure. Fluoro waxes work well
Race in the Woods: The snow will stay cold and have sharper crystals, wax for colder conditions. At Giants Ridge I consistently see racer test skis in the stadium, under the sun and warm conditions and then are surprised at how slow the warm waxes are in the woods.
Wet New Snow: Use fluoro waxes, wax for warmer than expected temperatures, use lots of structure.
Fine Dry New Snow: Wax for colder than expected conditions and temperatures.
Low areas near open water: Colder and more humid than expected.
Old Dirty Snow: Use fluoro waxes
and add structure.