It is starting to get hot in Northern California. I, like a million other people in the area (not an accurate statistic, but I’m assuming a lot), don’t have AC in my house. If you are one of these people, than you have also followed this statement with the perfunctory explanation of “but that’s ok because we don’t really need it”. And while I (a Central Coast town native with a temperature comfort range of 55-75) thinks it gets ridiculously hot here, I do acknowledge we are much more reasonable than many other places in the country. However, that doesn’t mean that the handful of 100+degree days don’t suck, or think the regularly occurring 90-degree days are comfortable.
Air conditioning is a rather new development, invented in 1902 to reduce humidity in a print shop; by 1931 the window unit was created, but was only accessible to the very wealthy. It wasn’t until the 1950s that a residential AC unit became a standard household feature. Central air didn’t come around until the 1970’s. Until then, people kept cool by smartly-designed houses that were custom to their climate and area, and following old-fashioned ways to stay cool.
If your home is like mine, where a summer day means your coconut oil easily melts in your pantry (which is at 76 degrees, btw), and putting in an AC isn’t financially feasible, or you have AC but want to reduce your energy consumption, consider following these simple tips to stay comfortable!
How to Stay Cool without AC
Don’t generate heat. If it is hot outside, avoid making more heat inside. Skip the dry cycle on the dishwasher, and do loads at night. Line dry clothes instead of using the dryer. Replace incandescent bulbs and halogens to LEDs. Take cooler showers, and run the exhaust fan to pull out humid air. Use a grill outside, or make quick meals on the stove instead of using the oven.
Take advantage of cool air. The easiest way that I keep my house cool is using my windows. Open up windows early in the mornings and then close them when the day starts to get warm. Open back up in the evening and night. I find that in Santa Rosa, I leave them open until around 8am, and then open them back up around 5:00, when the afternoon breeze comes in. Or on a really hot days, when the temperature equalizes with outside, around 4:00, and I just suck it up for a few hours.
Cross-ventilate. Open windows on opposite sides of the room, or if they are all on one side, set up a fan near the solid wall to direct air flow. If your house is two-story, open windows on both floors. Open the windows wider on the upper level than the lower to increase air flow speed. If you have fans, run them. Fans don’t change the temperature, but the moving air makes it feel that way.
Use curtains to block sun. Especially on the South and West facing windows, cover with dark shades to block out the sun, and therefore the heat.
Make your own shade. For a long term solution to heat management, plant trees on the East, West & South sides of your home, to cast shade, therefore keeping your home cooler. Highest priority is the South-West side, which will shield the hottest afternoon rays. Choose a deciduous tree, so that you can get warming sun during the winter. Or, consider awnings or trellises over windows. I recently read this article that talked about how air conditioning allows architects to be lazy, as we don’t need to think of way to vent warm air, how to shade windows. If you are remodeling your home, brainstorm and research ways to decrease heat in summer and increase heat in winter, and see if you can implement those in your building.
Adjust personal routines. People all over the world live in hot climates without AC, but instead utilize time-tested techniques to stay cool. Drink plenty of liquids, but limit caffeine and alcohol. Enjoy spicy foods and hot teas, which make you perspire, and therefore cooling you down. Wear loose clothing of natural materials, like cotton or linen. Do physical work during the cooler parts of the day, and find a shady spot to relax in during peak heat.
forgotten skills 
Those are all great tips. I use them myself here when it gets hot in summer. It does work!
We did most of those growing up in the Willamette Valley. Texas has A.C. Period. The nights in the summer cool down to maaaybe 78, but for stretches often 85 is as cool as the nights get.
I understand that folks lived here before AC, but I really wouldn’t have chosen to myself back then.