Looking on the internet deeply has found these results:

it rained is the most popular phrase on the web.

it was raining 1324,000 results on the web	it rained 19,620,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Bollywood film simultaneously made in English and Bengali. Written and directed by Indian actor It Was Raining That Night is a Hollywood It Was Raining That Night (2005). 105 min /10 X. Ratings: 8.1/10 from 21 users. Reviews: write review · Add a Plot ... director Mahesh ... Drama. 8.1. Your rating: 1 2 3 4 5 6 7 8 9 10 Jun 30, 2011 ... Regarding the diary or journal specifically, you might consider also to express it as past. It was raining the whole day is pretty clear ... He came on Friday, on which it was raining hard. Those two sentences are from my grammar book. It says when equals on which, and both of ...	And the park rangers confirmed that it rained the night before Samantha was killed. The crops weren't good last year, it rained all summer and ruined the harvest. They were coming on too late when it rained. Plus, it rained practically every day. Last night it rained and the wet moss is very green. Every time it rained, we had to kill the power. Means the hole was dug the night it rained. Last July in Houston, Texas, it rained for two days, 162 billion gallons.

it was raining

1324,000 results on the web

it rained

19,620,000 results on the web

More popular!

Bollywood film simultaneously made in English and Bengali. Written and directed by Indian actor
It Was Raining That Night is a Hollywood
It Was Raining That Night (2005). 105 min
/10 X. Ratings: 8.1/10 from 21 users. Reviews: write review · Add a Plot ...
director Mahesh ...
Drama. 8.1. Your rating: 1 2 3 4 5 6 7 8 9 10
Jun 30, 2011 ... Regarding the diary or journal specifically, you might consider also to express it as past. It was raining the whole day is pretty clear ...
He came on Friday, on which it was raining hard. Those two sentences are from my grammar book. It says when equals on which, and both of ...

And the park rangers confirmed that it rained the night before Samantha was killed.
The crops weren't good last year, it rained all summer and ruined the harvest.
They were coming on too late when it rained.
Plus, it rained practically every day.
Last night it rained and the wet moss is very green.
Every time it rained, we had to kill the power.
Means the hole was dug the night it rained.
Last July in Houston, Texas, it rained for two days, 162 billion gallons.