The most probable cause is too much water at one time. We got 3 inches of water last week and many pots don’t drain very quickly.The weather has also been cooler than the temperature tomatoes prefer. They are happier with temps in the 70s. 
If heavy rain  is predicted or there is a lot of rain if you can drag your pots under an awning or cover them with light plastic to keep them moist but not soggy that will prevent leaf curl from too much water. Covering them is a little risky because if the plastic stays stuck on the leaves the leaves will be damage. 
Check too that your plants are in big enough containers. See the  link for a few more causes of leaf curl.
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-leaves-curling.htm

https://www.epicgardening.com/tomato-leaves-curling/

https://extension.sdstate.edu/why-are-my-tomato-leaves-curled

https://hyg.ipm.illinois.edu/article.php?id=498

Thanks for your quick reply and information.

Thanks, let’s hope it warms up just a bit, tomatoes will be happier.