Applying rather to summer or spring

Hello everyone, 

I am a French student wondering whether it's better to apply to a spring program or a summer one. I am entering my first year of my master's next year, I graduate in 2026 or 2027, depending on whether I take a gap year or not.

I am looking for someone who could have an opinion on there's type of profile that would be better suited for a spring or summer (in France, most students are selected for spring programs and attend them during their first year of master, and convert into a summer program one year before the graduation). I would apply to the program where I would have more chances, and I wonder whether the full-time offers are flexible around starting if I happen to graduate later. I am looking forward to applying to programs in the UK and EU.

Thank you very much