Effects — wind, density altitude, microbursts
**Wind** is the dominant hazard for sUAS. Headwind reduces groundspeed and range; tailwind increases both but masks the risk of running the battery below the reserve needed for return. Most consumer-grade sUAS have a documented wind-limit of 25-30 kts sustained; operations beyond that risk lost-link or loss of control.
**Density altitude** (DA) is pressure altitude corrected for nonstandard temperature. High DA (hot + high + humid) reduces propeller thrust and battery performance. A 10°C temperature increase over standard raises DA by approximately 1,200 ft. sUAS climb rate and hover ceiling degrade proportionally.
**Microbursts** are small-scale, intense downdrafts (3,000-6,000 fpm) that can overwhelm any sUAS. Duration is typically 5-15 minutes; horizontal winds at the base can reach 45 kts. Operations near thunderstorms — even dissipating ones — should be avoided. Virga (precipitation that evaporates before reaching the ground) is a strong microburst indicator.
**Turbulence** from mechanical sources (buildings, terrain) and thermal sources (afternoon over paved surfaces) affects control authority. Flight during the stable part of the day (early morning, late afternoon) minimizes thermal turbulence.