Hello Di,
You know .. mostly it depends on the region , the east , the west will be more window in relation to the North , which will be better.... than these other region.
You wont be wearing big jackets. July is the start of winter. Yet in the north you can swim.
Comparatively to Mediteranean , it will be approximately the same temperature .
the sea temp will be round 25 degrees.
Enjoy,
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