I got these black spots on my apples few days back after there were heavy rains for 5days . before Rains there were not presence of these spots
You most likely describes a fungus called apple scab (Venturia inaequalis). Compare to the photo in fig. 1 in that link.
The relation to rainfall is a good observation:
Conidia, produced in large numbers, are washed or splashed to new locations during rain.
As usual when dealing with diseases, then it is highly important to remove infected leaves and fruits completely from your garden before winter to avoid new infections in the spring.