Когда ехать
Jun–Sep full access; May/Sep shoulder mud; winter north only.
Окна
- Июн–авг — all roads; Jul RV army book lodging year ahead.
- Сен — elk rut Mammoth; fewer kids school; some snow Sep 20.
- Май — mud season partial open; bison calves cute cold night.
- Окт–апр — most lodges closed; Mammoth + snowcoach only.
- Jul 4 week — 2× traffic Grand Loop plan 05:00 starts.
Что ломает пlan
Fire/Tornado road closure — detour 3 h check nps.gov/alerts. Bear jam — 1 h single lane Lamar photo idiot. Grand Prismatic parking full 10:00 — noon hike Fairy Falls instead.