Great question! Pets need to accliimate to warmer weather just like humans do! Start with short excursions and slowly increase the distance/time. Avoid the warmest time of the day. For pets walking on asphalt or sand, protect those tender pads by using booties or avoid those surfaces. Even a day in the high 70s/low 80s can make those surfaces blistering hot. Know the signs of overheating before things get too serious. https://www.petmd.com/dog/emergency/common-emergencies/e_dg_heat_stroke Sometimes, as much as it breaks their heart, leaving your pet home is the best decision.
What a good girl, Hadley!
I personally try to choose trails based on having a dog along. I don't know your area, so I can't speak to that, but I choose less spectacular hikes in favor of creek-side hikes to nothing much. There is one I go back to regularly that is down inside a gorge and the rock cliffs really keep it cooler even in the heat.
If that's not an option consider car camping and a small kiddie pool for the dogs to cool off.
We used to have a hard time keeping our large, black dog cool. Last summer we bought a Ruffwear swamp cooler jacket and it has been incredible! You get it wet before you start hiking and as the water evaporates through the special fabric it really cools your dog down. Even when we are in the direct sunlight and it's really hot, Otis will be cool to the touch under the vest. He loves it and it makes me way less worried about him overheating.
If I'm hiking in an area without streams to rewet it, I will bring an extra liter of water with me to replenish the vest once it has dried off. It can be a little tricky to get it fully soaked by just pouring water on it (the water likes to just run off), so I bring a gallon Ziplock, and stick the vest in the Ziplock with some water and mash it around so it absorbs the water and I don't waste any!
Spot on, great suggestion! We love our dog cooling jacket as well! I will be practicing your ziploc bag trick, as it's genius!
I am definitely interested in hearing how everyone is keeping their pup cool. I have a St Bernard and anything over 65 degrees is too hot for him. Our summertime adventures are quite limited. My last dog was a leonberger and he had a pack that he would carry when we went camping/hiking. I used to have a first aid kit and some cold packs, along with a water bottle, collapsable bowl and snacks.
In hot weather, I choose my hiking routes based on availability of water for my dog to swim in. Some of my hiking buddies also bring ice water in insulated bottles, and they sprinkle it on their doggies as needed to cool down. They seem to really appreciate it!