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Extreme Heat in Duval County

Each summer, residents and tourists enjoy the warm weather and sunny beaches in Jacksonville. However, it's important to be aware of the potential for extreme heat. High temperatures can pose significant health risks, as they can strain your body's ability to regulate its temperature. If the body cannot cool down quickly enough, serious health issues may arise. To keep everyone informed and safe, the National Weather Service issues alerts and warnings when there is an excessive heat risk in Jacksonville. 
 

Use the map below to locate places where you can stay cool and out of the heat during the summer months in Duval County. 

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Stay Safe in Extreme Heat

Heat Alerts and Warnings
Monitoring for Heat Advisory or Excessive Heat Conditions
BE AWARE!
The potential for Heat Advisory or Excessive Heat conditions will be highlighted in the NWS Jacksonville Daily Briefing and via official NWS Jacksonville forecasts.
Excessive Advisory
BE PREPARED!
A Heat Advisory is typically issued within 12 hours of forecast heat index values in the 108-112°.
Excessive Heat Advisory
TAKE ACTION!
A Heat Advisory is issued within 12 hours of the onset of extremely dangerous heat conditions, when the maximum heat index temperature is expected to be 100° or higher for at least 2 days, and night time air temperatures will not drop below 75°.
Excessive Heat Warning
TAKE ACTION!
An Excessive Heat Warning is typically issued within 12 hours of the onset of extremely dangerous heat conditions when the maximum heat index is expected to be 113°F or higher for at least 2 hours.
During Extreme Heat

Stay Cool:

  • Avoid Peak Heat: Avoid Peak Heat: Minimize outdoor activities during the hottest part of the day, typically between 10 a.m. and 4 p.m. If you must be outside, find shade and take frequent breaks in cooler areas.

  • Dress for the Weather: Wear lightweight, loose-fitting, and light-colored clothing to allow your skin to breathe. Opt for breathable fabrics such as cotton to help evaporate sweat and keep your body cool.

  • Seek Air-Conditioned Environments: Spend time in air-conditioned places like malls, libraries, or community centers to escape the heat.

  • Protect Children and Pets: Never leave children or pets unattended in vehicles, as temperatures can quickly become dangerously high and potentially fatal.

Stay Hydrated:

  • Drink Plenty of Water: Hydrate throughout the day, even if you don’t feel thirsty. Dehydration can occur rapidly in hot weather.

  • Limit Alcohol and Caffeine: Avoid excessive consumption of alcohol and caffeinated beverages, as they can increase dehydration.

  • Encourage Hydration: Remind family and friends to drink water regularly.

Stay Informed:

  • Monitor Weather Updates: Keep track of weather forecasts and heat advisories. This will help you plan your activities, avoid extreme heat, and take necessary precautions.

  • Recognize Heat-Related Illnesses: Be aware of the symptoms of heat exhaustion and heatstroke, which include dizziness, nausea, rapid heartbeat, and confusion. If you or someone else experiences these symptoms, seek medical help immediately and move to a cooler environment.

Heat Related Illnesses
Children under 4, adults over 65, and people who are overweight or ill are especially at risk of heat-related illnesses. Here’s how you can recognize heat-related illness and what you should do.

What are heat cramps?
Heat cramps are the mildest form of heat illness and consist of painful muscle cramps and spasms that occur during or after intense exercise and sweating in high heat. Symptoms include:
  • Painful cramps, especially in the legs
  • Flushed, moist skin 

What to do if you have heat cramps:

  • Replace carbohydrates and electrolytes by eating a snack with carbs (bananas) or drinking a sports beverage with electrolytes; Do this a few times an hour to prevent cramps from returning
  • Cool down and get out of the heat
  • Gently massage and stretch the cramping muscle
  • Apply an ice pack to the muscle

What is heat exhaustion?
Heat exhaustion is more severe than heat cramps and results from a loss of water and salt in the body. It occurs in conditions of extreme heat and excessive sweating without adequate fluid and salt replacement. Heat exhaustion occurs when the body is unable to cool itself properly and, if left untreated, can progress to heat stroke.
  • Muscle cramps
  • Pale, moist skin
  • Usually has a temp over 100.4° F (or 34° C)
  • Nausea
  • Vomiting
  • Heavy Sweating
  • Headache
  • Fatigue
  • Weakness
  • Anxiety, and faint feeling
What to do if you experience heat exhaustion:
  • Move to a cooler location
  • Lie down and loosen your clothing
  • Apply cool, wet cloths to as much of your body as possible
  • Sip water
  • If you have vomited and it continues, seek medical attention immediately

What is heat stroke?
Heat stroke, the most severe form of heat illness, occurs when the body's heat-regulating system is overwhelmed by excessive heat. It is a life-threatening emergency and requires immediate medical attention. Symptoms include:

  • Warm, dry skin
  • high fever, usually over 104° F (or 40° C)
  • Rapid heart rate
  • Loss of appetite
  • Nausea
  • Vomiting
  • Headache
  • Fatigue
  • Confusion
  • Agitation
  • Lethargy
  • Stupor
  • Seizures, coma, and death are possible‚Äč
What to do if someone is experiencing heat stroke: 
  • Call 911 immediately — this is a medical emergency
  • Move the person to a cooler environment
  • Reduce the person's body temperature with cool cloths or even a bath
  • Do NOT give fluids
If you have any of the following conditions, it’s important to be cautious during days with excessive heat warnings:
  • Heart disease: Heat increases the risk of heart attacks, arrhythmias and heart failure; These symptoms can include chest pain, shortness of breath, chest tightness, irregular heart rate, nausea, swelling of lower extremities and fatigue
  • Asthma/COPD and any chronic lung disease: Hot and humid air can cause airways to tighten and narrow and make breathing more difficult.  These symptoms can include wheezing, coughing, shortness of breath, chest tightness and fatigue
  • Mental Health: More instances of suicide, homicide, violent crime occurs on extremely hot days; Heat can exacerbate severity of symptoms in those with mental illness and lead to depression, anxiety, hallucinations and sleep disturbances
  • Diabetes: With extremes in temperature, those with Diabetes (types 1 or 2) have a more difficult time regulating body temperature and blood glucose. This can lead to dehydration, lightheadedness, nausea, and vomiting.
If you or someone you are caring for experiences any new or unexplained symptoms, please seek medical care promptly. Heat-related illnesses can escalate and pose life-threatening risks.
 
Impact of Heat on Medication

Medications That May Increase Heat Sensitivity
Medications Damaged by the Heat
Medications and Skin Sensitivity When Exposed to the Sun

Medications That May Increase Heat Sensitivity:

Medications can contribute to heat sensitivity by reducing the thirst sensation, interfering with mentation, decreasing perspiration, causing dehydration, low blood pressure and electrolyte imbalance.
Below are some examples:

Blood Pressure Medications:
  • Diuretics (such as furosemide, hydrochlorothiazide, acetazolamide) can lead to dehydration, electrolyte imbalance, increased risk of falling/fainting spells
  • Beta Blockers (such as metoprolol, propranolol, atenolol) can lead to decreased sweating, reduced blood pressure, increased risk of falling/fainting spells  
  • Calcium Channel Blockers (such as amlodipine, nifedipine, felodipine) can lead to reduced blood pressure and increased risk of falling/fainting
  • ACE inhibitors or ARBs (such as enalapril, lisinopril, ramipril, valsartan, losartan) decreased sense of thirst, reduced blood pressure, increased risk of falling/fainting
  • Nitrates (such as nitroglycerin, isosorbide mononitrate) can lead to significant low blood pressure, increased risk of falling/fainting
 
Mental Health Medications:
  • Mood stabilizer (such as lithium) can lead to diabetes induced water loss and risk of fainting falls and electrolyte imbalance. There's also a risk of lithium toxicity associated with dehydration.
  • Antipsychotics (such as haloperidol, risperidone, olanzapine) can lead to impaired perspiration which can increase body temperature
  • Selective Serotonin Reuptake Inhibitors (such as fluoxetine, sertraline commonly known as Prozac and Zoloft) this can lead to increased sweating
  • Stimulants (methylphenidate, dextroamphetamine commonly known as Ritalin and Adderall) can lead to increased body temperatures
  • Tricyclic antidepressants (such as amitriptyline) can lead to decreased sweating
Other Medications:
  • Anti-seizure medications (carbamazepine, topiramate, ox carbamazepine) can lead to body temperature dysregulation, increased urination, dizziness, weakness.
  • Older antihistamines (such as diphenhydramine commonly known as Benadryl) can lead to decreased sweating and impaired regulation of body temperature
  • Over the counter pain medications (such as ibuprofen, aspirin, acetaminophen) can lead to kidney injury with dehydration, increased body temperatures, liver injury with dehydration
  • Certain antibiotics (such as sulfonamides commonly known as Bactrim) can lead to kidney injury with dehydration
  • Certain HIV medications (such as indinavir) can lead to kidney injury with dehydration
  • Thyroid replacement (such as levothyroxine) can lead to impaired regulation of body temperature, constriction of blood vessels
Please remember that alcohol can lead to increased sweating, increased urination and impaired heat perception and is NOT considered as a way to hydrate.
 
 

Medications Damaged by the Heat:

It is important to note that medications may be damaged with heat exposure as well. Commonly affected medications would include:
  • Inhalers (used for asthma or COPD) that can actually burst in hot environments.
  • Epinephrine auto injectors (commonly known as Epipen) may malfunction or deliver less epinephrine when in hot environments.
  • Insulin should be stored in a refrigerator and may become less effective with prolonged heat exposure.
 

Medications and Skin Sensitivity When Exposed to the Sun:

Some medications can increase the sensitivity of the skin to the sun:  
  • Antifungal medications (such as flucytosine, griseofulvin, and voriconazole)
  • Certain Antibiotics (such as metronidazole, tetracyclines and fluoroquinolones commonly known as Flagyl, Doxycycline, Cipro, Levaquin) can increase sun sensitivity and lead to a sunburn-like rash.
For patients on these medications, sun avoidance, protective clothing and hats, and broad-spectrum sunscreen that filters out UVA and UVB rays, with an SPF of 30 or higher, are recommended.
 
 
 
Keep Your Pets Safe in Extreme Heat
  • Avoid dehydration: Pets can dehydrate quickly, so give them plenty of fresh, clean water.
  • Don't leave your pet in a parked car: ON A WARM DAY, the temperature in a car can exceed 120° in a matter of minutes—even with the windows partially open. Your pet can quickly suffer brain damage or die from heatstroke or suffocation.
  • Walk your dog in the morning and evening: When the temperature is very high, do not let your dog linger on hot asphalt or concrete. Your pet’s body can heat up quickly, and sensitive paw pads can burn.
  • Know when your pet is in danger: Symptoms of overheating in pets include excessive panting or difficulty breathing, increased heart and respiratory rate, drooling, mild weakness, unresponsiveness, or even collapse.

Stay Informed

Register for ALERTJAX notifications so you can be informed when potentially dangerous heat impacts Duval County. 

Download and print our Extreme Heat Safety flyers to help vulnerable members of our community stay safe when temperatures rise. 

Extreme Heat Safety (English)
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