Temperatures will go from warm to warmer this week with widespread triple-digit heat by mid-week in Southern California.

Temperatures Tuesday through Friday in the valleys and inland communities will reach triple digits. Expect highs in the mid- to high-90s in the Los Angeles basin and high-80s on the coast for the rest of the week.

“It’s going to sizzle, and it’s only going to get hotter in the coming days,” said NBCLA forecaster Belen De Leon. “We’re bracing for a heat wave starting tomorrow and lasting all the way through Friday with a moderate to high risk for heat illness.”

On Monday, the high will reach 90 degrees in the LA basin with triple-digits in the Antelope Valley.

Temperatures are expected to increase by a few degrees each day this week with the high reaching 94 in the LA basin by Wednesday. Triple-digit heat will spread into the Santa Clarita and San Fernando valleys Tuesday and the San Gabriel Valley by Thursday.

Nighttime temperatures will remain in the 70s in the valleys this week.

An excessive heat watch for all of Southern California with the exception of coastal communities will begin Tuesday and continue through Friday. Thursday and Friday will be the warmest days of the week, when temperatures will run 10 to 15 degrees above average.

Elevated wildfire conditions will accompany the hot and dry weather in the mountains, valleys and deserts.

Scroll for tips to stay cool this week.

• Stay hydrated! The more hydrated you are, the more effective your body will be at keeping you cool. Drink water – not fizzy and alcoholic drinks, which will dehydrate you.
• Avoid exercise in the middle of the day. If you need to exercise outside, do it early in the morning when the temperature is lower.
• Wear lightweight, light-colored natural fabrics like cotton and linen, as these will help your skin breathe and let your sweat evaporate, cooling you down.
• We sweat around half a pint daily from both feet (and we wonder why they stink!), so if you can, wear sandals or flip-flops to let your foot sweat evaporate.
• Use a fan to circulate air from open windows. Keep your blinds or curtains drawn during the day, so your home doesn’t heat up while you’re out. Turn off big appliances and help prevent brown-outs!
• To cool down quickly, run your wrists under a cold tap or keep a water spray in the fridge for a quick cooling spritz to the face.
• Keep some wet wipes in your bag so you can freshen up your hands, face and neck if you get hot or clammy.
• Want to stay cool at night? One way is to wash your feet in cool water or take a cold shower before bedtime – especially if you get hot during the night or have hot sweats.
• To cool down in bed, try keeping your pillowcase or sheets in a plastic bag in the fridge during the day. Put them back on the bed at night. The fabric will stay cool when you’re trying to get to sleep.
• And bring your pets in and make sure they have shade and water.
• Be prepared for power outages and know where cooling centers are!