Lesson 4: Rain, Humidity, and Wet Conditions
Wet conditions change golf in multiple ways — and physics explains all of them.
Rain means more friction between the ball and the ground when it lands. A shot that would roll 20 yards on a dry fairway might only roll 5 yards in wet conditions. This affects every distance calculation a golfer makes.
Wet grass between the club face and ball reduces spin — particularly backspin. This is called a flier lie — the ball launches with less spin, flies farther but lands with less control and runs more. Skilled golfers aim shorter to account for this.
High humidity actually makes the air slightly less dense because water vapor is lighter than nitrogen and oxygen. Very humid air creates slightly less drag — a small effect, but at high levels of play every small effect matters.
Wet fairway = more friction after landing = ball stops sooner.
Wet grass between club and ball = less backspin = flier lie = ball runs out more.
High humidity = slightly less dense air = slightly less drag.
Wet vs. dry landing test: find a grassy slope. Roll a golf ball down when dry and mark where it stops. Then wet the slope thoroughly and roll from the same point. How much sooner does it stop? Measure the difference. Write in your journal: what is causing it to stop sooner, and how would a golfer need to adjust?
The wet-vs-dry experiment is most vivid on a slope where the dry roll is at least 10-15 feet. The difference in stopping distance is usually dramatic and immediately connects to the practical question: how far will it run out after landing?