Heads up from a Southern Californian that it is time to buy any fans and/or KN-95 masks for the summer NOW, before the start of summer and wildfire season!!!
If you wait until your AC goes out to make sure you have enough fans, there will not be fans available for you to buy. If you wait for a wildfire, no one will have KN-95s for you to buy. They will all be sold out, especially as climate change makes summers more and more severe, and fire season longer and longer.
Other tips for keeping cool in extreme heat:
Do not ever leave a child or a pet in the car while it is off. Ever. Not "just for a few minutes," nothing. Kids have died from being trapped in hot cars in temperatures as low as 70 degrees F (21 C)
Especially if you live somewhere that doesn't typically get hot, make sure you own at least 2 tank tops and 2 pairs of shorts if at all possible. Thrift them or search them on Buy Nothing/something similar if you don't have them already. You will want the option
Cotton fabric evaporates moisture quickly and sheds heat fast. Cotton clothes are great for the heat for that reason, and if you're really desperate for relief, get cotton shirts/towels/cloths wet and either wear them or hang them up in front of a fan. The fan will blow the cooler, moist air throughout the room, cooling things down
Open windows and doors on opposite sides of rooms to create airflow
Hydration tablets and electrolyte drinks are magic for dehydration. You need to replace the salts you're sweating out. Salty trail mix is also great for this (you eat it on hiking trails for a reason)
Make sure your pets stay cool! Cold packs inside fabric can be really good for this (and for you!)
Most efficient place for a cold, wet towel to cool you down is the sides of your neck, your hands, and the soles of your feet (but NEVER put ice against your bare skin!)
Don't really expect anything of yourself between 1pm and 4pm - that is the hottest part of the day, and so it's the time you need to be the most chill (ba-dum tss). Movement creates heat (hence why you shiver, hence why exercising warms you up), so try to do as little as possible, and especially try to save errands and exercise until dusk
Many places now have heat shelters. Look them up in your area. The public library is often a spot for these, and if not, still a really good and FREE place to stay all day with AC
Plants cool things down. Standing on the grass will leave you measurably cooler than standing on the asphalt two feet away. Stay on plants, stay in the shade, and do what you can to add plants and green spaces to your area, to help keep it cool
If you live in a wildfire hotspot, try your best to get an air filter or air purifier now, because there will be none left by the time you need one
If you do end up near a wildfire zone: any smoke you can smell is smoke that can affect your lungs. Leave the house as little as possible (except to evacuate, which you should do as soon as an evacuation is called for your area). Duct tape the seams around windows and exterior doors to help keep out the smoke. And pack a go bag (change of clothes, toiletries, important documents, medications, spare food and water, essentials for pets or kids)
My qualifications: Lived in California my whole life, most of it in Los Angeles, and half my adult life living in buildings without AC. One time I went to a baseball game in 117 degree weather (47 C) and genuinely had a good time. I know things about keeping cool
Adding onto this: if you are sealing your house to avoid smoke coming inside, you need to be aware of CO AND CO2 buildup indoors. An air purifier does not remove CO2 or carbon monoxide, and both can suffocate you indoors.
