Year's First Significant Heat Wave Ongoing in the Southwest; 120-Degree Plus Heat in Death Valley

Linda Lam
Published: June 18,2015



 
The first significant heat wave of the year is sweeping into the Desert Southwest this week, pushing temps above the 120 degree mark in a few spots. High and low temperatures will be up to 15 degrees above average for much of the region.
(FORECAST: Death Valley, California | Las Vegas | Phoenix)
The hot temperatures have already reached record levels for late-June in some locations. Phoenix tied daily record highs on Wednesday (114 degrees) and Thursday (115 degrees). Palm Springs, California, reached 116 degrees on Thursday, breaking its daily record of 115 degrees.
Desert locations below 3,500 feet will continue to see temperatures rise well into the 100s, while the Colorado River Valley is even hotter with highs in the 110s. The hot spot as usual will be Death Valley, which could see temperatures over 120 degrees.
The National Weather Service has issued an excessive heat warning, effective now through next Monday for the Greater Phoenix area and the deserts of southwest Arizona, including Yuma. An excessive heat warning has also been issued for Thursday through next Monday for the Death Valley and Las Vegas areas.

Current Temperatures

The region's hottest weather so far this year is courtesy of high pressure is moving into the area. The National Weather Service in Las Vegas notes that gusty southwesterly winds are anticipated each afternoon, and along with near-maximum solar radiation as the summer solstice approaches, there is no reason to doubt the very warm temperatures ahead.
The air is also bone dry, another factor that allows temperatures to heat up quickly. In fact, Las Vegas reported an air temperature of 107 degrees at 3 p.m. Tuesday while the dewpoint was zero degrees, making the relative humidity an incredibly low 2 percent.
As is often the case this time of year, the nation's hottest temperatures have been in this region over the past few days. The nation's high was in Death Valley on Monday and Tuesday, with highs of 120 and 117 degrees, respectively. Needles, California, took the prize Wednesday with a high of 118. Thursday's hot spots were Blythe, California, and Thermal, California, which both topped out at 119 degrees.
These hot conditions will last through the weekend. This is a change from the first half of June which frequently experienced below-average temperatures and even saw wet conditions. Phoenix has seen 0.19 inches of rain this month and the average rainfall in June is 0.02 inches.
(MORE: Strange Early June Rain in the Southwest)
Temperatures in Las Vegas will reach or exceed 110 degrees Friday into the weekend, where the average high temperatures for mid-June are around 100 degrees. Highs in Las Vegas reach or top 110 degrees about 9 times a year; the record is 29 days in 1940.

Forecast Highs

Highs in Phoenix may reach the mid-110s into the weekend. Lows will add to the effect of the heat with temperatures only dropping into the 80s overnight within the urban areas; average mid-June lows in the Valley of the Sun are in the upper 70s.
This weather pattern may bring some additional record high temperatures (current records are in parentheses):

• Phoenix –  Friday (115 degrees).
• Tucson, Arizona – Friday (112 degrees) and Saturday (110 degrees).
• Las Vegas – Saturday (113 degrees in 1961).

We urge you to take safety precautions against the heat during this period. The National Weather Service in Phoenix warns that those playing or working outdoors, as well as those without access to air conditioning, will face an elevated risk of heat-related illness. Remember to never leave kids or pets unattended in cars, drink more water than usual. Wear light-colored clothing and keep your head and body cooler with a hat. Take frequent rest breaks in shaded or air-conditioned environments.
(MORE: All-time Record June Heat in the Northwest)

120-degree Heat Facts

Death Valley is one location that regularly experiences temperatures rising above 120 degrees. The average first date of the first 120-degree reading is June 25 and the earliest on record was on May 20, 2008. This year, Death Valley recorded its first 120-degree day on June 14 with a high of 121 degrees.
(MORE: Death Valley Flowers Bloom in Winter)
On average, Death Valley bakes under 120-degree heat on 15 days a year -- two days in June, eight in July and five in August. The most on record is 52 days in 1917 and there have been a few years with no days at or above 120 degrees -- most recently in 1965.
Occasionally 120-degree temperatures are reached as early as May (which last occurred in 2008, which saw 32 days above 120-degrees total) and sometimes the heat persists into September -- most recently in 2007 with 3 days topping 120 degrees.
Death Valley saw its first 100-degree temperature on March 28 this year when the thermometer reached 102, which was earlier than its average first 100-degree reading (April 19).
(MORE: Record March Heat)
The top three years for most days above 120 degrees in June are 12 days in 1961, 10 days in 1929 and eight days in 1994 and 1924.
In 2013, temperatures reached 129 degrees on July 1. The official world-record high temperature of 134 degrees occurred in Death Valley on July 10, 1913.
Phoenix has reached 120 degrees three times on record (twice in June 1990 and on July 28, 1995). Yuma, Arizona, has also reached 120 degrees a handful of times with the last time being in July 1995.
MORE: Extreme Places - Death Valley (PHOTOS)