How hot is it going to be in Denver this weekend? Dangerously hot, meteorologists warn.

The City and County of Denver said it is opening cooling centers this weekend after the National Weather Service issued heat advisories across the metro area.

All of Denver’s recreation centers and libraries will be open this weekend for residents to cool off from extreme temperatures that could reach triple digits.

Recreation centers will be open during regular business hours and library hours can be found on the city’s website. More information about cooling centers is available by calling (720) 865-5444, the city said.

The National Weather Service in Boulder on Friday said the heat advisories are in effect from 11 a.m. to 9 p.m. Saturday and Sunday and will stretch from Denver north to the Wyoming state line along the Interstate 25 corridor and east to the Greeley area as well.

In Denver, highs are expected to hit 99 on Saturday and 100 on Sunday. Both of those would tie the all-time record for July 25 and 26, respectively, according to weather service archive data. The 99-degree record on July 25 was last reached in 1963 and the 100-degree record high on July 26 has been standing 116 years, since 1910.

The extreme temperatures put Denver in a level 3 “major heat risk” zone, according to the National Weather Service, which means it will affect anyone without proper access to cooling and hydration. It’s also expected to impact health systems and industries.

Tips to beat the heat

City officials warned that the high temperatures could cause heat illnesses, which can be exacerbated by certain health factors such as age, obesity, dehydration, heart disease, poor circulation, sunburn, prescription drugs or drug and alcohol use.

The Colorado Department of Public Health and Environment advises residents to stay inside in air conditioning as much as possible and limit outdoor activity.

“Air conditioning is the No. 1 way to protect yourself against heat-related illness,” health officials said.

If you have to be outside, be sure to reapply sunscreen frequently, pace yourself, wear loose, lightweight, light-colored clothing and pay attention to the signs of heat illness.

Health officials also warned residents to drink more water than usual, even before becoming thirsty.

Fans don’t prevent heat-related illness when it gets this hot, so opt for a cold bath or shower instead, health officials said.

Ovens and stoves will only make your house hotter, so avoid using them. And also be aware that alcohol, caffeine and some medications such as antidepressants can increase the risk of heat-related illnesses.

Know the signs of heat illness

Health officials warn that heat stroke can be fatal if not treated quickly, so it’s important to know the early symptoms.

Muscle cramps, dizziness, weakness, headache, nausea or vomiting and dry or cracked lips can all be early signs of a heat-related illness, officials said.

More severe signs include red, hot or dry skin, elevated body temperature, a racing heartbeat, confusion, agitation, fainting or unconsciousness.

How to keep animals safe in extreme heat

Be sure to keep animals in the shade or cooler areas, and don’t cover, crate or confine the animal.

If you suspect an animal has heatstroke, cool them off with water or an ice pack on the stomach only, Denver Animal Protection said. Dunking the animal in water can hurt them even more if they’re unable to regulate their body temperature, officials said.

Never leave animals in a vehicle when temperatures get this extreme. Good Samaritan laws provide legal immunity to break a car window to save an animal if it is in imminent danger, the vehicle is locked and you’ve made a “reasonable effort” to find the owner, DAP said.

If you see an animal in a hot vehicle, call 311 or (720) 913-2080.