I call summer, "pony tail" season. I get one last trim before summer starts and that's it as my hair is pretty much up in a pony tail all summer.
Try using a couple elastics on a pony tail. The first one in the usual place, right against the head. Then place one half way down the tail to hold the hair straight & together. If your hair is really long, place another near the end. I do this right after washing. I don't bother drying my hair, just pony tail it in place. Then when it's dry, I let out the tail. All the elastics have kept the hair straight till dry and throughout the day.

So you may have pony tails in all your daytime pics. Then, when indoors at restaurants for dinner, have your hair down. But, at least your hair will look normal in some of your pics.
I also do "co-washing" with my hair, where I use hair conditioner to
wash my hair. (Google it.

) Basically, one hair product will work to dissolve & wash out other hair products. So using only conditioner WILL clean the hair & scalp without stripping the hair of essential oils and leaving it too dry. (Basically the WEN condtioning cleansers ares simply conditioner as shampoo, but you pay more than just picking any conditioner that works for you.) You do have to do more work to really work in the conditioner into the hair strands & scalp, AND to really rinse it out well, especially underneath at the scalp. Shampoo, on the other hand is thin, made to be sudsy and slide really easily by itself along the hair without much work. But, conditioner is purposely made thicker to stay in place, so one must move it along by hand, rub it in and rinse out really well. Or your hair could be accidentally left greasy feeling, especially the scalp by your neck, due to conditioner not being washed out fully.
I use a cheap conditioner for the quick wash, Anti-frizz VO5 with morrocan oil. I get it from the Dollar Tree for a dollar.

It's thin and I can put a lot on to cover my hair without it getting expensive like the previously mentioned WEN conditioners. Saturate hair really well before applying. As a PP said, hair loves & NEEDS moisture. The conditioner will seal in the moisture while you are cleaning the hair. Then once it's rinsed out, I follow up with a good THICK conditioner: Garnier Fructis Triple Nutrition conditioner. (Orange bottle.) I don't put it on near the scalp. Just more towards the top sections that will get all frizzy and especially on the ends. Rinse as usual.
When I do leave my hair down, I will follow all the above with Vidal Sassoon, Pro Series: Repair spray & finish. It's a leave-on spray. Comb the wet hair as little as possible. Spray on & rub into hair. Don't comb. It does get crunchy when dry. And I have to un-crunch my hair a little. But, my hair is not frizzy.
