Some would argue that Memorial Day is the unofficial start of summer.

After all, pools across the nation open for the first time on Memorial Day, and it's a day full of baseball and grilled meats for many, all summery activities.

But is it the true unofficial start to summer? In Arizona, not quite.

Last: Summer solstice

The official start of summer is the worst unofficial start.

By June 20, we've usually seen dozens of days with triple-digit highs, so summer has already begun. It's just here to let us know that we have so far left to go before we can start bragging about our warm days while the rest of the country wallows in wintry weather.

11. Memorial Day

It's a day to remember those who gave their lives for our country.

Because of its placement in late May, it's also a signal of summer's start, but the holiday aspect takes away from the fact that it should be a sobering day.

10. First 100-degree day

Living in Arizona, we've adapted to the idea that triple-digit highs aren't as big a deal as they are in other places (after all, it's a dry heat).

Call us when we hit 110.

9. No more hiking in the daytime

Say goodbye to that mid-morning trip up Camelback Mountain. You'd better be planning for a sunrise hike if you want to avoid a mountain rescue in the Arizona summer.

8. First day at the pool

Unlike apparently everyone in the Phoenix area, I'm not someone who enjoys the pool (just check out my farmer's tan).

But the first trip to the pool (and the corresponding first full-body sunburn) is a universal sign for the start of summer.

7. Moving your patio inside

In the summer, your patio becomes an indoor patio.

Whether it's to protect your furniture from heat-induced warping or keeping your plants alive, the transition is a sign that you're in for the hot summer.

6. First night of no blanket on the bed

When you finally transition to sheet-only sleep, you know summer is here.

The final step is sleeping on top of the covers, which makes falling asleep nearly impossible.

5. The first time you plan a trip to avoid the heat

Have to go to the grocery store? It better be your last stop if you don't want your ice cream to melt or your lettuce to wilt.

And if you've ever added a stop on a walk just to feel some AC, you know the struggle.

4. No more windows-down driving

This is a very sad day for those who love feeling alive.

Driving with the windows up and AC on just isn't as life-affirming. But it's necessary in 115-degree heat.

3. Major League Baseball's opening day

The smell of the grass, the roar of the crowd -- there's just something amazing about the beginning of baseball season.

The dog days of August are still far away and everyone's tied for first place.

2. Turning on the air conditioner

We tend to be pretty prideful about this one, holding off as long as possible before dusting off the AC dial.

While there's the added bonus of saving on the electric bill, keeping the air conditioning off is about showing you can take the Arizona heat more than anything.

When you finally give in, it's summertime.

1. School's out for summer

That final bell signaling the end of the school year may be the sweetest sound in academia.

It's also the best unofficial summer starter in the world, thanks to the joy it brings.