Ventilation in summer without controlled residential ventilation is problematic

Hello, I have now conducted various research efforts and am not becoming any wiser in this field. On various pages and sources of information, it is always said that you should ventilate early in the morning or late in the evening in summer, as it is usually cooler outside than inside at those times. However, it is also often stated that the humidity outside should naturally be lower as well. But when observing the values, the humidity is often quite high in the early morning or evening during summer, or am I mistaken? When should I ventilate on hot summer days? Not ventilating at all doesn't help either if it becomes too humid inside (basement around 65 percent, for example). Can someone clarify this for me or give me a tip? I would appreciate it.

In my opinion, it is always dry in summer, especially when it hasn't rained for a while. I know the tip to ventilate in the morning or evening for pollen allergy sufferers. If your basement is cool, you have to be careful with ventilation because the warm air then condenses on the cool basement walls. I can't imagine that there are humidity problems in the living areas in summer, no matter when you ventilate.

Sorry but what are you trying to tell me with that? I have to ventilate at some point. And even in inhabited rooms, you can ventilate very incorrectly in the summer. Just take a look at the current humidity values for the next few days. They are generally quite high. I can't not ventilate my basement all summer either, especially when too much humidity accumulates there.

The air in summer here is not dry.



If it's cooler outside than inside, ventilate, quite simple. PS the controlled residential ventilation users turn off the ventilation during the day.

I haven't been able to raise the humidity in our apartment anywhere near 40% for weeks, no matter when I ventilate. I explained it to myself by thinking that the air is generally dry because there is too little rain. I thought you are not allowed/should not turn off a controlled residential ventilation system because then the pipes would get contaminated? Our last controlled residential ventilation system didn't even have an off switch. For the basement, there are, for example, dew point-controlled fans. However, it is not clear to me whether you have a utility basement or a living basement.

Humidity levels for the next days

Where can I find them? The only percentages my weather app shows me relate to the chance of rain.