How it's calculated
Air. Air density comes from altitude and temperature (standard atmosphere, dry air). Carry changes by half the change in density: about +1.7% for every 300 m higher, and about the same for every 10 °C warmer.
Grass test. From your height, chest height is taken as 72% and a walking step as 41.5% (standard body proportions). Grass falls at roughly 1.5 m/s, so from chest height it is in the air for about a second; drift divided by that time is the wind near the ground. The wind is stronger higher up where the ball flies, so the app scales it to the usual 10 m wind of a weather report (about ×2 over short grass). For your height, one step of drift is about 6 km/h. Grass that falls faster or slower than assumed shifts this by up to a third.
Wind. Only the part blowing along the target line counts. Into the wind costs 1% per mph (0.62% per km/h), helping wind adds 0.5% per mph (0.31% per km/h). Woods react 20% less, wedges 20% more. Crosswind doesn't change the distance here.
Total. Roll-out stays the same in meters; Wet then takes off its own amount. Not included: humidity, a cold ball, firm or soft ground.