Bad news for anyone watching their electricity bill, another heat wave is on its way to Long Beach this week.

Temperatures are expected to rise into the low 90s late this week, with humidity remaining unusually high throughout the week.

The National Weather Service has issued a heat advisory that will be in effect from 10 a.m. Wednesday through 8 p.m. Monday, warning of a high risk of heat-related illness for sensitive populations.

The worst of the heat is expected to peak on Thursday, before slowly dropping heading into the weekend.

Warm ocean temperatures — the El Niño that’s only expected to strengthen in coming months — pump “a lot of relatively warm air onshore” and are to blame for the humidity, according to the NWS.

Relative humidity is expected to reach the low 80s each day this week before peaking at 90% on Friday.

That above-average humidity means temperatures will remain high at night, with lows in the high 60s to low 70s expected through Monday.

Also complicating this week’s weather picture are tropical storms Elida and Fausto, both in the Pacific Ocean well off the coast of Los Angeles.

Tropical Storm Elida will reduce the cloud cover as it moves north out of the region on Tuesday, but Fausto could increase clouds and moisture, resulting in cooler temperatures, as it moves west.

Don’t sweat it. Cool off here:

For anyone who needs relief from the heat, air conditioning is available at cooling centers throughout the city, including all public libraries. You can find a full list of locations and when they’re open here.

Long Beach also has aquatic playgrounds set up at Alamitos Beach (between Fifth and Sixth places) and at Bay Shore Beach. Those are open daily from 10 a.m. to 7 p.m., but all participants must pass a swim test before playing.

Public pools are available at Martin Luther King Jr. Park (1910 Lemon Ave.) and Silverado Park (1540 W. 32nd St.). Children age 17 and under can swim for free, while the entry fee is $3 for adults and $2 for seniors — defined as anyone age 50 and older.