Problem with brown lawn patches

I would stay away from mineral fertilizers. I tried it once and had to mow the lawn once a week from then on because that stuff made it grow so damn fast. to the OP: Just wait and see what happens. If necessary, just sprinkle a few grass seeds over the spots and that's that. Of course, it could be that you prefer a uniform appearance like an English lawn. (isn't the case for me)

We already had it in places that were not walked on, back in autumn. I believe it is snow mold.

I probably overdid it with the grass seed, the lawn was too dense and still grew very strongly in autumn and therefore too long. Not enough air gets to it and that's why these fungi grow.

It will probably go away on its own when it gets drier. If necessary, you can help a bit with lime, I have read.

I would stay away from mineral fertilizers. I did that once and then had to mow the lawn once a week because the stuff grew so terribly fast.

to the OP: Just wait and see what happens. If necessary, just sprinkle some grass seeds over the spots and that’s it. Of course, it may be that you care about a uniform appearance like an English lawn. (not the case for me)

Only once a week? In early summer I mow every two days, in late summer twice a week. The lawn loves it.

Only once a week? I mow every two days in early summer, twice a week in late summer. The lawn loves that.

The German civil servant just has time. ;)

*rofl*

Only once a week? I mow every two days in early summer, and twice a week in late summer. The lawn loves that.

Oh, really!
Well... for the used half of the property, the goal is once or twice a month, for the unused half once a year. Both are areas in the four-digit square meter range.
Among other things, we have lizards on the property and we don't mind if they feel comfortable. On the contrary! They should stay because they eat insects that literally ruin what we grow.
This doesn't work with intensively maintained lawns, and we only know chemical treatments from textbooks.
Some neighbors are a bit bothered by the relatively natural setup and always point out that "...the stuff growing there just seeds itself..." but they forget that our property borders 80 hectares of grassland and their fears represent David's struggle against Goliath.
Other neighbors think it's cool. ;)

BTT:
As I said, the OP should wait and see first. If something turns brown, it’s not bad but completely normal.
The growing season will start again soon, and then the problem should solve itself. Allegedly, it helps to mulch once just before the growth begins because the regrowth is better protected against drying out.

The German civil servant just has time. ;)

Obvious