It’s hard to resist names with Summer in them, because it’s a handy trope with lots of positive connotations. Summer (no matter which months of the year it happens in) is a good time for passion projects and the like. Plus there is the trend established by the “Google Summer of Code”, “Rails Girls Summer of Code”, “Infinite Summer”, etc.
At least when I was in New Zealand I could just inverse the seasons to see what USA based companies and people were talking about when they referenced their seasons. Now I have to do a mental calculation (which is hard to remember, as as I said, you don't get seasons here at all) to work out time frames when people are talking about stuff like this.
A decent chunk of the population of the planet (most of it, I think?) lives around the equator