What marks summer's arrival for you?

I saw a blog today from fellow City-Cost contributor TheMuggleWriter1997, asking if summer has arrived yet. It prompted this blog, because I think maybe that's a different answer for everyone, to a degree!

Of course, there's the official start of summer marked by the solstice, but I think some of us might mark it from the first day we have to use our air conditioners, or when the temperature hits a specific number for the daily high. Maybe it's when we see certain flowers start to pop up, or when seasonal snacks like all things choc-mint hit convenience store shelves. 

However, I had to cackle at this Reddit post I saw earlier this week, which marked the start of summer in a somewhat unconventional way.

What marks the beginning of summer for you?