Life-threatening heat engulfed much of the Western United States this past weekend. Above-average, triple-digit temperatures struck Phoenix, Tuscon, Los Angeles and other cities on Saturday, breaking records and prompting warnings from local officials. More than 200 all-time high temperature records were broken or tied in June this year, primarily in the Northwestern United States. Above-average temperatures were more widespread — 16 states logged above-average temperatures for the month. And a number of cities set all-time record highs.

Temperatures vary widely throughout the year, across North America, and over the course of history. The coldest temperature ever recorded in the continent was -81.4°F in Snag, a small village in Canada’s Yukon Territory. On the other end of the spectrum, temperatures reached a staggering 134°F in Furnace Creek, Death Valley, California on July 10, 1913.

Based on the most recent historical temperature data from the National Oceanic and Atmospheric Administration (NOAA), 24/7 Wall St. identified the cities where the hottest temperatures persist for the longest time. Yuma, Arizona leads the nation, with an average of 175 days of 90°F degree and above temperatures each year. By contrast, 73 cities report 10 or fewer days that reach at least 90°F.

Click here to see America’s hottest cities.

While exceedingly high temperatures can contribute to drought and wildfire conditions, residents of these areas are not strangers to scorching summer heat. Not only is it the norm, but some economic activity relies on the heat. Farmers, for example, require at least four weeks of dry, hot weather before they can harvest hay.

The hottest cities are concentrated in certain states. The three hottest cities are all in Arizona, another five are in Texas. The remaining two are in Florida and Nevada. All of the cities are in the South or Southwest, near major U.S. deserts.

Most of the hottest cities report very little precipitation over the year. While the majority of American cities see at least 100 days of rain each year, the annual average rainfall in all but two of the hottest cities does not exceed 75 days. It typically rains less than 20 days per year in Yuma, Arizona and Las Vegas, Nevada. More than half of the 10 hottest cities also have extremely low humidity levels.

To identify the hottest cities in America, 24/7 Wall St. reviewed the average number of days that temperatures of 90°F or higher were recorded in 274 U.S. cities. The statistics are from “The Comparative Climatic Data for the United States through 2012,” a report published jointly by the National Oceanic and Atmospheric Administration (NOAA), National Environmental Satellite, Data and Information Service, and the National Climatic Data Center Asheville, North Carolina. Averages for each city were calculated over periods spanning between 31 and 72 years, all through 2012. Record temperatures, monthly average temperatures, precipitation data, and annual average morning and afternoon humidity levels also came from the report. Precipitation data is based on the annual mean number of days with precipitation of 0.01 inches or more. The relative humidity is expressed as a percentage measure of the amount of moisture in the air compared to the maximum amount of moisture the air can hold at the same temperature and pressure. Average humidity values are given for morning and afternoon observations.

These are the hottest cities in America.

10. Waco, Texas
> Avg. number of 90°F+ days: 109
> Record high: 112°F
> Avg. daily temp. in August: 85.3°F

Based on 49 years of data, temperatures rise above 90°F 109 days per year in Waco, Texas, a longer average period of extreme heat than all but nine other cities. Most U.S. cities see at least 100 days of rain each year. Unsurprisingly, annual precipitation in most of the hottest cities, including Waco, is well below average. This area sees just 74 days of rain each year on average, one of the 50 lowest levels compared with all cities reviewed. So far this year, however, the state as a whole has experienced above-average rainfall. According to the NOAA, Texas recorded 24.04 inches of rain over the first half of this year, the wettest on record for the state.

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9. Austin, Texas
> Avg. number of 90°F+ days: 109
> Record high: 112°F
> Avg. daily temp. in August: 85.8°F

Austin is tied with Waco as the ninth hottest city in the country. Also like Waco, the hottest temperature ever reported in Austin was 112°F, a record set on September 5, 2000. The average temperature in August is 85.8°F, higher than all but four other cities in the NOAA database. According to the NOAA, daytime summer temperatures in Austin exceed 90°F 80% to 90% of the time.

8. San Antonio, Texas
> Avg. number of 90°F+ days: 113
> Record high: 111°F
> Avg. daily temp. in August: 85.8°F

Half of the hottest cities in America, including San Antonio, are in Texas. The Gulf of Mexico, which is to the east of the city, lowers the average temperature, according to the NOAA. Still, San Antonio sees 113 days of 90°F and above each year, and summers are typically very long and bring blistering heat. The hottest temperature ever recorded in the city was 111°F in September 2000, relatively late in the year. The Gulf also contributes to above-average humidity levels, which in San Antonio are typically above 80% in the morning, and around 60% in the afternoon.

7. Fort Myers, Florida
> Avg. number of 90°F+ days: 113
> Record high: 103 °F
> Avg. daily temp. in August: 83.4°F

While most of the nation’s hottest cities are also relatively dry, Fort Myers reports both above-average rainfall and especially high humidity levels. The city receives 105 days of rain each year on average, and humidity approaches 90% in the early part of the day. The maximum temperature recorded in the city, at 103°F, was also lower than many of America’s other hottest cities. Still, Fort Myers is undeniably one of the hottest places to live. The annual average temperature is 75.1°F, one of only six cities reviewed where the yearly average temperature exceeded 75°F.

6. Brownsville, Texas
> Avg. number of 90°F+ days: 124
> Record high: 106°F
> Avg. daily temp. in August: 85.3°F

Brownsville is located on the Gulf of Mexico, at the southern tip of Texas. The city saw above-average temperatures over 25 consecutive months through April 2013. While subsequent years were more mild, the area still reports some of the most consistently high temperatures in the nation. With the Gulf so close, Brownsville has a humid, subtropical climate. The average relative humidity is 88% in the morning and 70% in the afternoon, each among the highest humidity levels of any city nationwide. However, like most of the nation’s hottest cities, Brownsville reports relatively few days of rainfall — on average, it rains 65 days per year in the city. By contrast, in Chicago, and Boston, and New York, it rains on average at least 100 days each year.

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5. Del Rio, Texas
> Avg. number of 90°F+ days: 129
> Record high: 112°F
> Avg. daily temp. in August: 86.2°F

Del Rio, on the Rio Grande in southwest Texas, is one of the hottest and driest cities in the country. Temperatures exceeding 100°F have been logged as late as October and as early as March. The highest temperature recorded in the city was 112°F on June 9, 1988. And for over 50 days from June 17 to August 5, 1980, the temperature remained above 100°F, the longest such stretch ever recorded in Del Rio. Unlike several other cities on this list, Del Rio receives no relief from a nearby large water source like the Gulf of Mexico. Instead, the city faces the desert heat of the American Southwest.

4. Las Vegas, Nevada
> Avg. number of 90°F+ days: 133
> Record high: 117°F
> Avg. daily temp. in August: 90.6°F

During the month of August, the temperature in Las Vegas hovers around 90°F, the third hottest August among cities reviewed, and one of only a handful where average summer temperatures exceed 90°F. The city is located an hour and a half from Laughlin, Nevada, where on June 29, 1994, the temperature reached 125°F, the third highest ever recorded in the U.S. Las Vegas has been among the nation’s hottest cities for many years. While it has reduced its water consumption dramatically, it still uses more water than most U.S. cities, and sees just 19 days of rain per year on average, fewer than in every city except for Yuma. And worsening drought conditions in the region may pose problems for the city in the near future. Lake Mead, which supplies 90% of Las Vegas’ water, is currently at near-record low levels.

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3. Tucson, Arizona
> Avg. number of 90 °F+ days: 144
> Record high: 117°F
> Avg. daily temp. in August: 84.7°F

Tucson is one of the three hottest cities in Arizona, which is the only state containing parts of four U.S. deserts — the Great Basin, Chihuahuan, Mojave, and Sonoran. Each year, the city sees an average of 144 days with temperatures exceeding 90°F, trailing only two other cities. Due in part to the extremely high temperatures, Arizona — and Tucson, in particular — experience annual monsoon thunderstorms from the middle of June through the end of September. Rainfall is still relatively uncommon in Tucson. The city sees about 44 days of rain each year, less than in all but 13 other U.S. cities.

2. Phoenix, Arizona
> Avg. number of 90 °F+ days: 169
> Record high: 122°F
> Avg. daily temp. in August: 93.6°F

Northwest of Tucson, and north of the Sonoran Desert, Phoenix is the second hottest city in America. Residents typically live in at least 90°F heat for almost half of the year. Phoenix is also one of only a handful of cities where the temperature typically remains above 90°F the entire month of August. This past June, meteorologists predicted record-breaking spans of high temperatures for the city. The longest stretch of extreme heat in Phoenix was in August 2012, when temperatures 110°F and above were recorded for 10 consecutive days.

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1. Yuma, Arizona
> Avg. number of 90 °F+ days: 175
> Record high: 124°F
> Avg. daily temp. in August: 91.9°F

The hottest city in America is Yuma, where 90°F or higher temperatures are typically recorded 175 days per year. The city saw temperatures reach a record high of 124°F in July 1995, also the highest recorded temperature of all the cities reviewed. The highest temperature ever recorded in the U.S. was 10 degrees higher, in Greenland Ranch, California, also known as Death Valley. Humidity tends to be highest in the morning. In Yuma, however, the average morning and afternoon humidity levels of 23% and 22% are inline with each other and both nearly the lowest such figures among all cities reviewed.

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