SAN FRANCISCO (KRON) — Memorial Day is by far the hottest day of 2021 for the Bay Area.

Temperatures in some places are expected to get into the triple digits, breaking records for high heat.

The North and East Bays will feel the warmest weather as the day goes on, the National Weather Service said.

With the blazing sun comes danger for fire and heat-related illnesses. A Heat Advisory will be in place from noon to 9 p.m. on Monday.

Firefighters have been responding to grass fires across the Bay Area and on Monday morning, there was a bit of a wake-up call in the Santa Cruz Mountains.

San Jose Fire Captain Mitch Matlow showed KRON4 how relative humidity had already dropped to 30-percent by 11:30 a.m. on Monday. He notes that anything below 40-percent is worrisome.

His truck is stocked with a good supply of cold water to help keep firefighters hydrated in the hot temps.

The holiday weekend, along with high heat and low humidity, is keeping firefighters busy.

Between Memorial Day and the upcoming 4th of July, the annual specter of fires sparked by illegal fireworks looms. As the worsening drought adds still more worry to the picture, community leaders are poised to renew the annual message to those who would break the law.

People planning to make use of their day off from work should avoid strenuous outdoor activity during the hottest time of the day – maybe keep the hiking and picnics to shady, tree-lined areas.

Try to stay in air-conditioned areas and drink plenty of water throughout the day.

Keep in mind that the pavement could be unbearably hot for dogs while taking them for a walk.

NWS also wants people who try to cool off at the coast to watch out for dangerous rip currents.