My car's navigation system is slow to turn on

Slurp! Such wise insight. High temperatures are a primary cause of electronic devices slowing down and malfunctioning. Devices may also reduce performance to cool themselves, so please park in the shade to manage the temperature. Don't forget to eat nutritious meals to avoid getting tired in the hot weather, hmm!

Since it's an electronic device and it's hot inside the car, it seems like that could be the reason.