You rarely need an anemometer. Leaves rustling and a flag stirring is force 2; whole small trees swaying is force 5; when twigs snap off and walking gets hard, you are into force 7. The land tells you the number if you watch it.
Wind near the ground is turbulent — friction tears the flow into eddies, so speed arrives in packets rather than a steady stream. A gust is just a larger eddy rolling past; the lull behind it is the gap before the next.
As slopes cool after sunset, the air against them chills, grows dense, and slides downhill. On a clear evening you can feel this drainage wind pick up in a valley even when the sky is perfectly still above.