Aguas Termales Santa Rita
It might not be an obvious bet to seek out natural hot springs in a warm weather destination, but the Aguas Termales Santa Rita are truly special. This divinely sculpted Jacuzzi is an enchanting place to soak and relax, and there's a refreshing, cool-water river bend just a few steps away, ideal for moving back and forth between the two. The smell of sulfur is strong, but you get used to it, and it does wonders for your skin and any body aches. Assuming you bring your own provisions, there are areas to sit and eat (complete with picnic tables and basic grills) and even overnight campsites. It's a long drive down a dirt road to get here, but it adds to the charm and adventure of the experience. You will not have cell reception, so downloading Maps in advance is a must. You'll need cash to pay the entry fee, collected presumably by the family who lives on the land.
Note: there are two hot springs compounds right next to each other, with separate entrances and fees. The first, Los Encinos, is not as nice as Santa Rita, but could be ideal for families with young children as the water is more shallow and space more confined, making it easier to supervise your brood. Everyone else should continue driving just another hundred yards more to reach Santa Rita.