Monsoon season punishes cars that weren't prepped for it — standing water, sudden downpours, and humidity all stress systems that go unnoticed the rest of the year.
Check wiper blades for cracking or a torn edge — a blade that streaks or skips during the season's first real downpour is a visibility hazard at the worst possible moment. Tyre tread depth matters even more in the wet; worn tread dramatically increases hydroplaning risk on flooded roads.
Inspect door and window seals for cracking, since a failed seal lets water seep into the cabin and accelerates rust from the inside out. Have your battery and electrical connections checked — moisture finds its way into loose or corroded connections and causes intermittent electrical faults that are maddening to diagnose later.
Avoid driving through standing water deeper than your wheel hubs — beyond that, water can be drawn into the engine's air intake, causing catastrophic hydrolock damage that a service department cannot cheaply fix. If you must cross floodwater, go slowly in first gear to maintain a bow wave ahead of the car rather than through it.