Aug 10, 2014

Why Is Phoenix So Hot?

Phoenix is famous for its scorching hot temperatures during the summer. Between June and August, the daily high temperatures can be over 110°F (43°C) for several days in a row.

So, why is Phoenix so hot? There are a variety of natural and man-made factors.

NATURAL FACTORS

1. No Sea Breeze
This might seem kind of obvious, but I'm going to cover it anyway. Many of America's major cities are coastal cities. San Francisco, Los Angeles, Seattle, NYC, Miami, and Chicago are all located near large bodies of water. The effect of wind blowing across the water provides a year-round cooling effect called a Sea Breeze. Because Phoenix is not located near any large bodies of water, the city does not receive this natural cooling effect.

2. Low Elevation
Another factor in a city's temperature is its elevation. Phoenix is about 1,080' above sea level. Compare that with cities like Las Vegas (elev. 2,030'), Salt Lake City (elev. 4,327'), Denver (elev. 5280'), or Albuquerque (5,312'). Lower elevations typically have higher temperatures because there is more air above them, which increases the atmospheric pressure.

3. Close to the Equator
You may recall from high school geography class that the world is divided into a system of vertical and horizontal lines called Latitude and Longitude.

Phoenix is relatively close to the Equator, at just 33°N Latitude. Las Vegas is at 36°N, Salt Lake City is at 40°N, Chicago is at 41°N and Minneapolis is at 45°N. (Keep in mind, the North Pole is at 90°N).

Near the Equator, Earth's atmosphere is very thin. This allows more of the sun's energy to be absorbed by the earth. Higher elevations are more protected against the atmosphere and thus have cooler temperatures.

4. Down in the Valley
Phoenix is located in the Salt River Valley - a low spot surrounded by mountains. These mountains block the wind and rain that would ordinarily be transported by a current of fast-moving air called the sub-tropical Jet Stream. Because of our natural barriers, Phoenix has over 300 days of sunshine per year.                                          

MAN-MADE FACTORS
 
5. The Heat Island Effect
Some of the factors in Phoenix's notoriously hot temperatures are due to man-made causes. One of these is the heat island effect.

Much of the city is paved with concrete and asphalt for roads, parking lots, driveways, and sidewalks. Pavement stores and retains the heat from the sun. What this means is that after the sun goes down, overnight low temperatures do not drop much as they would in an unpaved area.

So there you have it: five reasons why Phoenix is such a hot city during the summer.

Also, please remember that this article covers the climate of Phoenix. Other cities in Arizona including Flagstaff and Show Low have all four seasons.

10 comments:

  1. Impudent Observer4/29/2015 4:01 PM

    Great explanation! I really liked the comparisons of other cities thrown in. For instance, I had no idea Albuquerque's elevation is higher than Denver's!
    Thanks, and keep cool!

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  2. Which ocean is Chicago located near?

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    Replies
    1. The Mediterrenean, Dummy.

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    2. That’s not an ocean, dummy.

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    3. Chicago gets winds from being on shore of Lake Michigan, part of Great Lakes chain, but not ocean.

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  3. Ah good catch! In retrospect, "large body of water" would have been a better term.

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  4. That's 5 good reason's for calling this place "The valley of the sun"







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  5. I'd rather take the PHX heat, than sub zero Temp up north in the winter,😏💥PS I dispise cold frigid winters.. good for Eskimos and penguins

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  6. Some of these don't check out. Let's take Dallas, for example. Average summer temperatures are in the mid 90s - easily 10-15 degrees below Phoenix highs. Let's see how Dallas compares to your list:

    1. No Sea Breeze - check. Dallas is nowhere near a large body of water. The nearest large body of water is the Gulf of Mexico, which is slightly further from Dallas as the Pacific is from Phoenix.

    2. Low Elevation. check. Dallas is at an even *lower* elevation than Phoenix - 430 feet! Both #1 and #2 are checked by a large part of the midwest, actually.

    3. Close to the Equator: check. At 32.7N, it's actually slightly closer than Phoenix.

    4. Down in the Valley: this is the only checkbox that Dallas doesn't check.

    5. Heat Island Effect: check. Like most urban areas, this occurs in Dallas.

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    Replies
    1. And the valley makes the difference! Check out Redding, California. It’s further north than all other Central Valley cities, but it gets scorching hot in the summer. I think it’s the same principle. The sun beats off the south slope of the mountains and creates like a heat pocket. Maybe.

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