Is the Heat Index Real?

MarianVejcik/iStock via Getty Images
MarianVejcik/iStock via Getty Images

Complaining about the humidity is a mainstay of small talk. “It’s not the heat that gets you, it’s the humidity” is a common refrain around the South, just as “it’s a dry heat” is a go-to line in the desert Southwest. The clichés aren’t wrong on this one—a hot and humid day can have a dramatic effect on both your comfort and your health. We can measure this very real impact on your body using the heat index. 

The heat index is the temperature it feels like to your body when you factor in both the actual air temperature and the amount of moisture in the air. If the heat index is 103°F, that means that the combination of heat and humidity has a similar physical impact on your body as it would if the actual air temperature were 103°F. Even though it’s tempting to think of the heat index as an exaggerated temperature that only exists to make the heat sound worse than it really is, scientists came up with the measurements after decades of medical and meteorological research devoted to studying the impact of heat and humidity on the human body. It’s the real deal.

The dew point is an important component of the heat index. The dew point is the temperature at which the air would reach 100 percent relative humidity, or become fully saturated with moisture like on a foggy morning. Since cooler air can’t hold as much moisture as warmer air, lower dew points reflect lower moisture levels and higher dew points indicate higher moisture levels. Dew points below 60°F are comfortable, while readings reaching 70°F and even 80°F range from muggy to downright oppressive.

Measuring humidity on a hot day is important because moisture is how your body naturally cools itself off. Your sweat cools the surface of your skin through a process known as evaporative cooling. If the air is packed with moisture, it takes longer for your sweat to evaporate than it would in more normal conditions, preventing you from cooling off efficiently. The inability to lower your body temperature when it’s hot can quickly lead to medical emergencies like heat exhaustion or heat stroke, which is why the heat index is such an important measurement to pay attention to during the summer months.

The heat index is generally considered “dangerous” once the value climbs above 105°F, and your risk of falling ill increases the higher the heat index climbs.

Dry climates can have the opposite effect on your body, with the distinct lack of moisture in the air making it feel cooler to your body than it really is. Summers get oppressively hot in places like Arizona and Iraq, but the heat doesn’t affect residents as severely because the air is extremely dry. Dew points in desert regions can hover at or below 32°F even when the air temperature is well above 100°F, which is about as dry as it can get in the natural world.  

In 2016, a city in Kuwait measured the all-time highest confirmed temperature ever recorded in the eastern hemisphere, where temperatures climbed to a sweltering 129°F during the day on July 21, 2016. The dew point there at the same time was nearly 100 degrees cooler, leading to a heat index of just 110°F, much lower than the actual air temperature. That’s not necessarily a good thing. Extreme heat combined with extreme aridity can make your sweat evaporate too efficiently, quickly dehydrating you and potentially leading to medical emergencies similar to those you would experience in a much more humid region of the world. 

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This story has been updated for 2019.

Take Advantage of Amazon's Early Black Friday Deals on Tech, Kitchen Appliances, and More

Amazon
Amazon

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Even though Black Friday is still a few days away, Amazon is offering early deals on kitchen appliances, tech, video games, and plenty more. We will keep updating this page as sales come in, but for now, here are the best Amazon Black Friday sales to check out.

Kitchen

Instant Pot/Amazon

- Instant Pot Duo Plus 9-in-115 Quart Electric Pressure Cooker; $90 (save $40) 

- Le Creuset Enameled Cast Iron Signature Sauteuse 3.5 Quarts; $180 (save $120)

- KitchenAid KSMSFTA Sifter with Scale Attachment; $95 (save $75) 

- Keurig K-Mini Coffee Maker; $60 (save $20)

- Cuisinart Bread Maker; $88 (save $97)

- Anova Culinary Sous Vide Precision Cooker; $139 (save $60)

- Aicook Juicer Machine; $35 (save $15)

- JoyJolt Double Wall Insulated Espresso Mugs - Set of Two; $14 (save $10) 

- Longzon Silicone Stretch Lids - Set of 14; $13 (save $14)

HadinEEon Milk Frother; $37 (save $33)

Home Appliances

Roomba/Amazon

- iRobot Roomba 675 Robot Vacuum with Wi-Fi Connectivity; $179 (save $101)

- Fairywill Electric Toothbrush with Four Brush Heads; $19 (save $9)

- ASAKUKI 500ml Premium Essential Oil Diffuser; $22 (save $4)

- Facebook Portal Smart Video Calling 10 inch Touch Screen Display with Alexa; $129 (save $50)

- Bissell air320 Smart Air Purifier with HEPA and Carbon Filters; $280 (save $50)

Oscillating Quiet Cooling Fan Tower; $59 (save $31) 

TaoTronics PTC 1500W Fast Quiet Heating Ceramic Tower; $55 (save $10)

Vitamix 068051 FoodCycler 2 Liter Capacity; $300 (save $100)

AmazonBasics 8-Sheet Home Office Shredder; $33 (save $7)

Ring Video Doorbell; $70 (save $30) 

Video games

Nintendo

- Legend of Zelda Link's Awakening for Nintendo Switch; $40 (save $20)

- Marvel's Spider-Man: Game of The Year Edition for PlayStation 4; $20 (save $20)

- Marvel's Avengers; $27 (save $33)

- Minecraft Dungeons Hero Edition for Nintendo Switch; $20 (save $10)

- The Last of Us Part II for PlayStation 4; $30 (save $30)

- LEGO Harry Potter: Collection; $15 (save $15)

- Ghost of Tsushima; $40 (save $20)

BioShock: The Collection; $20 (save $30)

The Sims 4; $20 (save $20)

God of War for PlayStation 4; $10 (save $10)

Days Gone for PlayStation 4; $20 (save $6)

Luigi's Mansion 3 for Nintendo Switch; $40 (save $20)

Computers and tablets

Microsoft/Amazon

- Apple MacBook Air 13 inches with 256 GB; $899 (save $100)

- New Apple MacBook Pro 16 inches with 512 GB; $2149 (save $250) 

- Samsung Chromebook 4 Chrome OS 11.6 inches with 32 GB; $210 (save $20) 

- Microsoft Surface Laptop 3 with 13.5 inch Touch-Screen; $1200 (save $400)

- Lenovo ThinkPad T490 Laptop; $889 (save $111)

- Amazon Fire HD 10 Tablet (64GB); $120 (save $70)

- Amazon Fire HD 10 Kids Edition Tablet (32 GB); $130 (save $70)

- Samsung Galaxy Tab A 8 inches with 32 GB; $100 (save $50)

Apple iPad Mini (64 GB); $379 (save $20)

- Apple iMac 27 inches with 256 GB; $1649 (save $150)

- Vankyo MatrixPad S2 Tablet; $120 (save $10)

Tech, gadgets, and TVs

Apple/Amazon

- Apple Watch Series 3 with GPS; $179 (save $20) 

- SAMSUNG 75-inch Class Crystal 4K Smart TV; $998 (save $200)

- Apple AirPods Pro; $199 (save $50)

- Nixplay 2K Smart Digital Picture Frame 9.7 Inch Silver; $238 (save $92)

- All-New Amazon Echo Dot with Clock and Alexa (4th Gen); $39 (save $21)

- MACTREM LED Ring Light 6" with Tripod Stand; $16 (save $3)

- Anker Soundcore Upgraded Bluetooth Speaker; $22 (save $8)

- Amazon Fire TV Stick with Alexa Voice Remote; $28 (save $12)

Canon EOS M50 Mirrorless Camera with EF-M 15-45mm Lens; $549 (save $100)

DR. J Professional HI-04 Mini Projector; $93 (save $37)

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5 Ways to Help Victims of the West Coast’s Wildfires

A wildfire near Shaver Lake, California, earlier this month.
A wildfire near Shaver Lake, California, earlier this month.
David McNew/Getty Images

Wildfires continue to ravage millions of acres across California, Oregon, and Washington, and strong winds forecasted in some of those regions could aggravate the blazes. To prevent future fires, we need to focus on combating climate change through policy reform and sustainable living. But for people directly affected by the fires, their current needs are much more urgent: food, shelter, and funds. Here are five organizations that can help you help victims.

1. Red Cross

The Red Cross has about 600 workers coordinating meal distribution, installing victims in shelters and hotels, and providing other support across Northern California. You can donate to the cause by choosing “Western Wildfires” under “I Want to Support” on the donation page here.

2. GoFundMe

GoFundMe’s affiliated nonprofit, GoFundMe.org, has created a Wildfire Relief Fund for this particular outbreak of fires on the West Coast. You can make a donation to the overall fund here, or you can explore the separate hubs in the description to find individual GoFundMe pages to give to.

3. Los Angeles Fire Department Foundation

Unfortunately, the city of Los Angeles doesn’t allocate enough public funds to the fire department to equip firefighters with all the important gear they need. The Los Angeles Fire Department Foundation tries to fill those demands by providing things like hydration backpacks, thermal-imaging cameras, brush-clearing tools, and more. You can donate to the general fund here, or choose a specific fire station from the dropdown menu.

4. VEMAnet

VEMAnet (Volunteers for the Emergency Management of Animals Network), is an offshoot of the Good Shepherd Foundation, which links animal owners who need emergency help with volunteers who can transport and/or house their animals—anything from cats to cattle—temporarily. You can post details about what animals you can accommodate here; and if you or someone you know needs help evacuating any pets, you can request help or browse available listings here.

5. California Fire Foundation

The California Fire Foundation’s Supplying Aid to Victims of Emergency (SAVE) program distributes $250 gift cards to wildfire victims, so they can decide for themselves what their most pressing needs are. You can donate here.