My non-native English-speaking friend asked me the question, and I said one way, but her other native English-speaking friend said the opposite and I wanted to hear other opinions.
She asked, which of these is better (imagining you're on the top of a mountain):
We couldn't have come here if it was raining.
vs
We couldn't have come here if it had been raining.
I said I prefer the second, her other English-speaking friend said they prefer the first. Is there a difference? Are they both acceptable? Is it a regional difference?