There are some places I'd go out of my way to visit in July. Scandinavia and other Baltic cities are best in July and August. The north coast of Spain is also best in July/August.
Some - most of what you mentioned - I'd avoid. If the point is to loll on the beach, then going south is fine. If you intend to do a lot of walking and sight-seeing, the summer months will be the most expensive, crowded and miserable time to tour.
Many places like Netherlands, Belgium, England, Ireland, Scotland have a maritime weather pattern. They get rain any time of year but don't get as cold of winters as other parts of the continent. The countries with maritime weather will get marginally warmer and less wet during the summer months - but only relatively, you still want to travel prepared for anything up to, and including, a deluge.
The far northern countries, Scandinavia, Baltics, British Isles, also have a very noticeable difference in daylight hours between summer and winter. Traveling in the summer allows significantly more daylight hours to visit sights.