While it may seem like Labor Day marks the official end of summer, residents across several western states are experiencing a heat wave this week with temperatures exceeding 86 degrees Fahrenheit.

The National Weather Service has issued an extreme heat warning for Southern California, the southern tip of Nevada and western Arizona.

Temperatures are expected to rise over the course of the week, reaching as high as 47 degrees Celsius in desert cities like Palm Springs.

According to meteorologists, the heat wave will be highest on Thursday and Friday, mainly due to weak winds from the sea and a heat dome.

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In Phoenix, temperatures will range between 42 and 46 degrees Celsius every day this week.

Scripps News Phoenix said the record for days above 110 degrees was set last year with 55 days. They believe the record will be broken this week as they have already seen 54 days above 110 degrees.

On Tuesday, Phoenix reached 100 days in a row with temperatures above 100 degrees Fahrenheit, breaking the previous record of 76 consecutive days with temperatures above 100 degrees Fahrenheit, set in August 1993.

According to Scripps News Las Vegas, temperatures in Las Vegas will reach 106 degrees Fahrenheit every day this week. At night, temperatures will only drop to around 80 degrees Fahrenheit.

Meanwhile, temperatures in Southern California will be 5 to 15 degrees above average this week. Scripps News San Diego said inland and mountain areas could reach 108 degrees, while desert areas will see 108 to 116 degrees.

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Temperatures in Southern California will only drop slightly this weekend, but the added moisture from the monsoon will make it more humid, Scripps News San Diego reported.

The sweltering start to September offers no relief to residents who have already experienced the warmest meteorological summer on record, which ended in August for several cities.

The average temperature in Phoenix this summer was 100.4 degrees Fahrenheit, breaking last year’s record of 97.6 degrees Fahrenheit, according to Scripps News Phoenix.

In Las Vegas, the average summer temperature was 96.2 degrees, while the average high was 107.6 degrees. Scripps News Las Vegas said that in addition to reaching the highest daily high ever recorded — 120 degrees on July 7 — there were three other record-breaking days in July.

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According to Scripps News Las Vegas, Sin City recorded seven consecutive days of temperatures of 110 degrees Fahrenheit or higher for the first time in history. There were also 11 consecutive days of temperatures of 110 degrees Fahrenheit or higher.

The Centers for Disease Control and Prevention offers the following tips to protect yourself from extreme heat:

• Stay indoors in an air-conditioned room as much as possible.
• Drink enough, even if you are not thirsty.
• Plan outdoor activities carefully.
• Wear loose, light, light-colored clothing and sunscreen.
• Take a cold shower or bath to cool down.
• Visit a friend or neighbor and ask if someone else can do the same for you.
• Never leave children or pets in the car.