2004 Hyundai Elantra will not start after it rains

This problem started in the fall. When it rains the car would be a hard start with much “chuging” until it was warmed up enough to drive, then it would run fine. Last week we had a very heavy rain…and car would not start for 2 days. Any ideas on what might be getting damp?

Remove the spark plug cover and look for indications of moisture on the cover, on the coils and insulation and in the spark plug wells.