What Causes a Car to Fail to Start on Rainy Days?

[VanMackenzie]

Car fails to start on rainy days due to battery corrosion or leakage. On sunny days, you can move the car to a sunny spot to let it air out and dry, evaporating all moisture in the corners. At low temperatures, the battery's output power decreases because the electrolyte viscosity increases, reducing penetration ability and increasing resistance, making it difficult for the starter to turn the engine and reach the minimum starting speed, thus affecting engine startup. Additionally, the low terminal voltage of the battery results in weak sparks from the spark plugs, and the dense mixture increases the resistance between electrodes, making it hard to ignite the mixture, which also contributes to engine starting difficulties.

[LaRicardo]

I've been driving for over 20 years and often encounter this frustrating issue of the car not starting in rainy weather. The main problems lie in the ignition system - moisture easily gets into the engine compartment, causing the spark plugs and ignition coils to become damp and short-circuit; water accumulation at battery terminals can also lead to poor contact, preventing the starter from turning. Additionally, components like the crankshaft sensor may falsely report error codes when damp, making the system think there's a problem and refuse to start. The most annoying part is that high humidity during rainy days disrupts the air-fuel mixture ratio, resulting in poor combustion efficiency and failure to start. I remember one time my car got flooded and short-circuited directly, forcing me to push it away. Solutions include covering the hood or using waterproof cloth for protection after parking in the rain; waiting a while before starting to let moisture dissipate; regular maintenance with annual checks on ignition wires and battery sealing to ensure they stay dry. Replacing components before rainy season brings more peace of mind - safety first, don't force it, and seek professional repair promptly.

[StAndres]

As a new driver, I encountered this situation during last month's rainy season - the car wouldn't start no matter how I tried, which was really frustrating. There are several possible reasons: an aging battery performs poorly in humid weather, fogged connectors increase resistance and prevent current flow; rainwater splashing on high-voltage ignition wires causes short circuits, preventing spark plugs from igniting the gasoline; high air humidity affects engine air intake, making the combustion chamber too cold for proper ignition. I also learned that a failed water pump seal leaking into the system can worsen the problem. That time I had to call a tow truck to take it to the shop, where the technician said it was due to delayed maintenance and overdue part replacements - both costly and dangerous. He suggested we should always prioritize checking battery life and wire seals during maintenance, clean the engine compartment before rains to prevent water accumulation; when the car won't start, avoid repeated attempts as they drain the battery, wait for clear weather or try jump-starting instead; make it a habit to conduct comprehensive seasonal inspections to avoid roadside breakdowns that disrupt traffic.

[LaDelilah]

I don't drive much but have researched this. Common reasons for failure to start in rainy weather briefly: damp spark plugs failing to ignite, short circuits in ignition coils; water accumulation on battery terminals increasing resistance, insufficient power delivery; rainwater seeping into engine compartment damaging circuits. High air humidity leads to lean air-fuel mixture making combustion difficult. The solution is to dry water droplets promptly after parking, wait a few minutes before starting to dissipate moisture. If unsuccessful, seek professional repair assistance immediately to prevent potential hazards affecting driving safety.