Hello @GeminiTwin - Welcome! It's great to hear that you all are planning a trip to a national park. We're so glad you have found this community before you go. There is tons of information here that you can search through and there are many members with vast amounts of expertise to answer your questions on hiking gear! You might want to take a look at the hiking board to see if someone has already asked a question that you have. 

A big piece of advice for dressing well in fluctuating weather is to dress in layers. You can find lots of great information on the topic in our Expert Advice article titled How to Dress in Layers. You'll want to pay attention to the clothes' fabric as well since hiking in the summer often means sweating. Synthetic layers and wool will wick away sweat and keep you more dry than cotton, so that is a large factor to pay attention to.

It's great to hear you all already have boots, as you will want to break those in before you get out into long days on the trail. If they are new boots, we suggest you starting out with short walks so your feet can adjust to them, rather than potentially getting blisters while on your vacation.

You might also find it useful to schedule a free virtual outfitting appointment. During those appointments, you are able to video chat with an REI employee one-on-one to discuss the expected conditions of your trip and the different needs of each family member. You will then get personalized suggestions for clothing and other gear for your big trip! 

We look forward to hearing more of your questions and sharing our tips with you. Again, we're so glad you're here!

At REI, we believe time outside is fundamental to a life well lived.