How hot is it? Hot, hot, hot…

The Las Vegas Valley is expected to reach and even surpass 110 degrees later this week, marking the hottest day of the summer so far.

Temperatures soared to 108 at the official monitoring station at McCarran International Airport on Monday, but Thursday and Friday could hit 111, according to the National Weather Service. Temperatures are expected to reach 108 to 110 degrees over the weekend.

While it will be plenty hot, the 111-degree heat will not quite merit a heat warning, when officials urge people to take special precautions and stay out of the sun.

"If we're facing 112 -- which we're not yet -- we issue a heat warning," weather service meteorologist Andrew Gorelow said.

Gorelow said the 112-degree barrier is based on past heat death occurrences. The weather service and Clark County coroner's office jointly determine the cutoff, which fluctuates throughout the year.

Earlier in the summer, for example, the cutoff is 105 degrees.

"Once you get later and later into summer, people's tolerance gets better," he said.

But under a warning or not, Gorelow said, people should take it easy in such extreme heat. He suggested that they check on elderly neighbors and drink lots of fluids, especially water.

On average, temperatures rise past 110 degrees earlier in the summer, on July 1, weather service records show. The earliest the valley has broken 110 was June 8, 1978. The latest was Aug. 12, 1962.

Monday's record high, set in 1939, was 115 degrees, according to the weather service. Today's record high is 116 degrees, set in 1972. Las Vegas' all-time high temperature was 117 degrees, set in 1942 and tied July 19, 2005.