DENVER (KDVR) — The summer season is usually recognized as “starting” on the summer solstice, which is June 21 this year.

However, the seasons don’t change all at once and there are usually a few summer-like things that start to happen before the official start of the season.

FOX31 asked viewers what their Colorado signs of summer were.

Weather

Changing weather is probably one of the more apparent signs that a new season is fast approaching. The more the temperatures rise, the more clear it becomes that spring is over and summer is about to begin.

“Hot and dry during the day, and blissfully cold in the evening,” one viewer said.

However, some viewers pointed out that Colorado’s weather is not that predictable.

“[A] surprise snowstorm that angers everyone!” another viewer said.

Out-of-state license plates and tourists

Colorado residents aren’t the only ones who flock to the state’s many beautiful sights during summertime.

Some viewers pointed out that they know that summer has begun when they start seeing more and more out-of-state license plates on the road — mainly from highly populated states like California and Texas.

Those cars aren’t empty, either, as one viewer said.

“Tourists,” they pointed out. “All the happy tourists.”

Miller moths

If you live in the eastern part of the state and have noticed the huge population of moths recently, you are certainly not alone. Those are miller moths, and they’re completely harmless.

“All the moths flying around,” a viewer pointed out.

The miller moth migration season usually doesn’t extend into the summer season — experts said they appear around mid-May and are gone around early June. However, given their abundance and appearance right before the summer season, it is understandable that people would see this as a sign of the months to come.

Wildfires and smoke

Not everything that Coloradans have come to expect in summer is positive.

A few viewers pointed out that they know it’s summer when there are wildfires and smoke in the air.

Starting May 19, much of the eastern part of the state was covered in smoke from wildfires raging in Canada. During this, Denver’s air quality was among the worst in the world for a period time.

This might have impacted people’s answers, but given the Bureau of Land Management considers Colorado’s wildfire season to run from May to September, it isn’t far off to say wildfires and smoke are not uncommon in summer.

Outdoor activities

One thing that all of the above have in common is that they impact something Colorado is known for: The great outdoors. To go along with that, several people listed outdoor activities that let them know summer is here.

“When the water parks open!” one FOX31 employee suggested when brainstorming. Water World in Federal Heights opens on May 27 and Elitch Gardens typically opens its water park during Memorial Day Weekend. Chatfield State Park also opens its swim beach this weekend.

For the more adventurous, Mt. Evans Scenic Byway opens Memorial Day Weekend and crews at Rocky Mountain National Park aim to have Trail Ridge Road open at the same time.

Warmer weather also means people are able to get out for exercise. One viewer said they judge summer by an increase in cyclists on the roads, especially in the foothills.