Student or Learner
Please make this clearer:
I was partying at the club so I didn't come to know that it was raining but when I came out i saw that the road was wet so i came to know it was raining.
Using "I didn't come to know"..is this correct English
"I was partying at the club so I didn't realize that it was raining. But when I came out i saw that the road was wet so I knew it had been raining."
"I was partying at the club so I didn't find out / discover that it had been raining until I came out and saw that the road was wet."
"Come to know" is rarely used in standard English in this context.
If you came out of the club and it was still raining, you wouldn't have to look at the road - so I've changed your "was raining" (which means "is raining" in this context) to "had been raining".
"I found out is was raining" - It's still raining. "Was" is used because of backshifting of the tense.