Wind, waves and fetch
Waves grow with wind speed, how long it blows, and the fetch: the open distance it blows across (NOAA JetStream). On a big lake, an offshore wind can push a kayak away from shore faster than you can paddle back. Our conditions check uses caution above 20 mph gusts (Beaufort force 5) and flags hazardous at 32 mph (force 7) (NWS Beaufort scale; NWS wind safety).
Educational summary of the cited sources, not a safety guarantee. Check local conditions and wear a life jacket.