Go to dressing index in May and July.

The temperature difference in Germany is relatively large. May is still relatively cold, it may be within 10 degrees in the morning and 20-23 degrees at noon, usually with long sleeves and a coat. It will be a little hotter in July, but basically the highest temperature will not exceed 30 degrees. You can wear short sleeves, but you should wear long sleeves if it gets cold occasionally.