Aviation Weather Sources and Effects on sUA Performance
Sources
Use aviationweather.gov for METARs (current surface observations), TAFs (terminal forecasts), and area forecasts. A METAR reports wind, visibility, clouds, temperature/dew point, and altimeter. TAFs cover a 24–30 hour window. Also check NOTAMs and TFRs. For sUA, pay special attention to the surface wind group, gusts, and the difference between sustained wind and gust spread.
Weather Effects on Small Aircraft
Small UAS are light and low-inertia, so wind is the dominant hazard. A headwind reduces groundspeed and battery range; a tailwind increases groundspeed and can push you past the 87-knot limit or beyond visual line of sight. Gusts cause attitude disturbances and can exceed the aircraft's control authority. Density altitude matters: high temperature, high elevation, and high humidity reduce air density, which reduces propeller and motor performance and lift. Cold temperatures reduce battery capacity and voltage sag. Precipitation, especially rain, can damage exposed electronics and obscure the camera. Fog and haze cut visibility below the 3 SM minimum.
Traps
Questions often ask which weather product gives a forecast versus an observation (TAF vs METAR), or test whether a tailwind helps or hurts (it hurts: faster groundspeed, less range, possible speed violation). Another trap: assuming humidity has no effect on performance - it does, via density altitude.
Rule of Thumb
Compute density altitude mentally: for every 1,000 ft of elevation and every ~8°C above standard, expect noticeably degraded climb and endurance. If gusts exceed roughly half the steady wind or approach the aircraft's rated wind limit, scrub the flight.