They should do just fine outside with the rain. Remember these plants came from outside over thousands of years. If you are worried you could always give it a little shake in the AM to shed some of the water.
Here is the rule with rain and our plants outside. Rain with sun after to dry is ok. Rain with no sun after and no airflow is bad. This can harbor mold. I only had an issue outside once when I had a stretch of rain with no sun and no wind for a few days.
If you are very worried you could cover the plant with a tarp and remove it in the AM. People do this a lot, just remember to remove it.
Hope this helps.