Thanks for all the replies.
I saw that Harris sells slitted row cover:
https://www.harrisseeds.com/storefro...d-6-x-250.aspx
They also sell a punched hole row cover:
https://www.harrisseeds.com/storefro...d-6-x-250.aspx
I have no idea which of the two products would be better for tomatoes. Maybe slitted, so the plants don't get wet on a cold rainy day?