Heat alerts warning of dangerous weather conditions are in effect for each of San Diego County’s climate zones through Wednesday as a stifling heat wave reaches its peak. An extreme heat warning was in effect through 8 p.m. Wednesday for San Diego’s coast, inland valleys and deserts, where d angerously high temperatures could be as much as 10-15 degrees above average. But the heat won’t come to a grinding halt; as soon as the heat warning expires, a heat advisory will go into effect through Thursday evening. The mountains are under a heat advisory through 8 p.m. Thursday. At the coast, where temperatures typically grace the upper-70s at this time of year, are expected to be in the mid-80s amid the heat warning. The National Weather Service issues these warnings because heat illnesses increase during periods of extreme heat. Residents are urged to drink plenty of fluids, stay in air-conditioned rooms and stay out of the sun. Never leave pets or children unattended in vehicles. “Car interiors will reach lethal temperatures in a matter of minutes,” the NWS said. Dozens of locations across San Diego County act as “Cool Zones,” providing a space where residents can seek relief from the heat for free. See the list here. Adding to the uncomfortably is excessively high humidity stemming from a mix of monsoonal moisture and heat rising from warmer-than-usual ocean temperatures, according to the NWS. Tropical storms hundreds of miles away, like the recent Hurricane Marie, can also increase humidity. While Marie continues to weaken, much of the county will continue to feel its muggy effects and the mountains may see some afternoon thunderstorms. Those seeking relief at the beaches will be met with a coastal flood advisory and a high surf advisory through 11 p.m. Tuesday due to the storm’s linger swells. Swells could reach about 6-7 feet and cause tidal overflow during evening high tides, the NWS said. Swimmers and surfers were urged to use caution amid dangerous conditions, including possible rip tides. While some relief will come Thursday and Friday, lower humidity and cooler temperatures are not likely to come before next Sunday, according to the NWS. This story uses functionality that may not work in our app. Click here to open the story in your web browser. ...read more read less