It’s very rare in my opinion for people to take 4 consecutive weeks off. I’m in the UK where we have generous leave compared to the US but slightly stingy compared to continental Europe. I work administratively in a university. The academics get a lot of leave (more than admins etc) and it’s very common for them to take 2 or even 3 consecutive weeks off in the summer, and/or in December combining with xmas closure. For administrative jobs, it’s quite common for people to take their leave in increments of a week at a time.

For people in retail sectors etc, I don’t think fully closing businesses is that common, except maybe small businesses, and I’d be very surprised if many people did it for more than a solid week. When I worked in retail full-time for a stretch of 18 months, I didn’t take any leave at all in that time except the occasional unpaid day but more commonly just a re-shifting of my schedule.

So most of the places you expect to be open (restaurants, leisure centres, theme parks etc) will be operating normal (or longer) hours in the summer so plenty to do. Also, a lot of uni/student workers will staff places like theme parks, hostels, etc during the summer. I worked all my uni summers in various places on seasonal contracts.

But it’s true that businesses with more traditional office hours (ie. Monday-Friday jobs) may have more staff off in the summer and therefore be less responsive – this is especially true in universities if you want to contact academic staff etc.

I remember when I started my internship in Germany; the hiring director was apologetic he could only offer me 4 weeks vacation to start.

Sigh.