Los Angeles marathoners will need to take extra precautions to stay cool at Sunday's race.
The National Weather Service says to expect "record-breaking heat" this weekend - up to 20 degrees above normal. Daytime highs are predicted to range from the 80s to lower 90s at the coast and the mid-80s to mid-90s in the valleys and foothills this weekend.
"As we hit Sunday, the hottest day of the weekend, we're expecting the heat will build and we will see mostly sunny skies," says NBC4 meteorologist Shanna Mendiola. "A few clouds out there but we are going to be talking record heat."
LA Marathon organizers have taken steps to help their runners beat the heat.
The full-field will begin 30 minutes earlier than scheduled, moving from 7:25 a.m. to 6:55 a.m. The 26.2-mile race will start in waves to "ensure proper runner spacing" and allow efficient supply restocking at 24 aid stations, according to an advisory on the marathon website. Those stations will be supplied with extra water, Gatorade, as well as cold towels and ice.
If needed, runners can take a break at numerous medical tents, misting stations or on 'cooling buses' along the course and at the finish line.
Organizers have even asked participants to consider running at a slower pace and not beat any personal records.
"We really just want to encourage runners to kind of dial it back and come out and just really enjoy the event but also to take personal responsiblity," says Tracey Russell, chief executive of the LA Marathon
NWS forecasters suggests that even residents not running the marathon avoid the heat by staying hydrated and scheduling outdoor activities for the morning or evening to dodge the highest temperatures. The weather service also recommends people wear light clothing if doing any strenuous activities - like running a marathon.
Marathon organizers say they will give regular updates on additional resources for the sold-out event.
Michelle Valles contributed to this report.