Where in the world is the summer climate cool and dry?

The temperate maritime climate is relatively suitable. Mainly distributed in Britain and other western Europe, the rest are distributed in the northwest coast of North America, southern Chile, southeastern Australia and New Zealand. The biggest feature is that the temperature is small all year round, but there are many rainy days.

In summer, the Mediterranean climate is controlled by subtropical high, with sinking airflow, hot and dry climate, less clouds and plenty of sunshine.

The continental climate doesn't have the characteristics you want at all.

Of course, there are many places that only satisfy what you call "cool and dry in summer", compared with many summer resorts in China, and so on.

You can learn more about climate in Baidu Encyclopedia.