AVG
Rolling ~2-min average. The steady wind you'd feel — use it to pick a kite size.
GUST
Strongest gust the station is reporting right now (peak of the latest reading). Tells you how hard the current spike is hitting.
PEAK
Strongest gust over the last 5 minutes. Slower to drop than GUST — captures whether conditions just spiked. Useful for "is it safe to launch right now".