Number of heat deaths in Clark County hits 342

The number of heat-related deaths in Clark County this year reached 342 as of today, county officials said.

The  number could actually be higher because it can take several months of investigation to determine if a death was caused by the heat, officials said.

Though Las Vegas is past the worst of its intense heat, the National Weather Service in Las Vegas said this summer was the hottest on record.

The weather service today issued an excessive heat warning for the Las Vegas valley from Friday through Sunday. 

Temperatures in July were 6.7 degrees hotter than normal, with an average of nearly 100 degrees, the weather service said.

On July 8, the temperature reached a record 120 degrees. And for seven straight days in July, temperatures hit at least 115 degrees.

At the beginning of September, there was an excessive heat warning for three days when temperatures reached 106 degrees.

Las Vegas hit 101 degrees at the Harry Reid International Airport on Wednesday, marking the 101st day of 100 degrees or higher this year. This year holds the record for the most days of 100 degrees or higher.

There was a 50% chance of Las Vegas reaching 100 degrees today, a 75% chance on Friday and 95% chance on Saturday.