Which one is correct?

[Mr_jim]

Which one is correct?why?

1>if it rained the day would have been ruined.

2>If it had rained, the day would have been ruined.

[Rusty]

Which one is correct?why?

1>if it rained the day would have been ruined. (Incorrect).

2>If it had rained, the day would have been ruined. (Correct).

Here is the Englishpage explanation. You can read more by going to http://www.englishpage.com and clicking "Conditionals." Your example is a Past Unreal Condition. (Had rained" is the past perfect form of the verb. "Been" is the past participle.

Past Unreal Conditional

FORM
[If ... PAST PERFECT ..., ... would have + PAST PARTICIPLE ... ]
or
[... would have + PAST PARTICIPLE ... if ... PAST PERFECT ...]

USE
The Past Unreal Conditional is used to talk about imaginary situations in the past. You can describe what you would have done differently or how something could have happened differently if circumstances had been different.