All my plants have these signs on scapes and leaves.
I thought about slugs but there is so hot and dry I don't think they are there.
We had a hailstorm some night ago but the signs were already there.
Should I check for slugs after sunset?

If they hadn't been there before I'd have said the white spots are probably hail. Do all your daylilies have them? Have you sprayed with anything?

I don't think the grooves are from slugs but wouldn't rule them out and other pests may come out at night so it's worth looking. One thing that got my attention is towards the top of the middle of the first picture. There's a white line that slightly squiggles. Can you see anything under the leaf surface there, and are there any more lines like that?

Thanks Sue, I should have wrote that the leaf is broken and I think it was hail to break it. Nothing under the leaves, today I cleaned and weeded and checked the plants.
I went out before and I couldn't see anything alive among the plants, then a thunderstorm and heavy rain came so I can't check now.

But these "scorching" are there since june/july and I was always forgetting to ask on here. One explanation could be a previous hailstorm by night.