When you initially put "houseplants" outside, you need to be careful about the strength of the sun..., many tropical plants and even cacti and succulents will burn unless acclimated. So, I keep mine shaded for a couple of weeks before putting them into sunnier locations. I am in NJ/Zone 7, but depending on the species..., mine will go out anytime from March to May 1st. I have so many plants that I have to do this all in waves (over the course of weeks). YEARS ago, I used to start taking things inside around Labor Day, but Autumns are SO much warmer now that I don't start now until late September at the earliest (and that's with the HYPER tropicals..., mangos for example. Citrus come in some time in late October around Halloween. First frost come around the first week in November. But it really does depend on what kinds of plants you are talking about..., many of my subtropical (palms and cycads for example), can take light frosts and may not get sheltered (in the garage) until December.

I send quite a few of my houseplants to Summer Camp. I think it's still fine to be putting them out now. Like blue bayou said, just don't put them in direct sun. Mine all go on the east side where they get filtered morning sun or on the back porch that is covered with one of those big sun sails. It's like a shade cloth. So they are getting indirect light. They all seem to love it.

In fact, I thought my sago palm was completely dead. All the fronds were brown, so I cut them off. I put the pot outside in a shady location and ignored it for the last month. Well, lo and behold, it's producing a new frond. It will probably die when I have to bring it back in. But it was fun while it lasted!

I am in East Tennessee. Our houseplants include pretty typical things -- monstera, pathos, schefflera, fiddle leaf fig, Christmas Cactus, etc. In early May, we take all of them onto our back screened porch. They thrive all summer and just seem in their element. When the nighttime temperature starts dipping down into the low 50s, we bring them back in, making sure they are all in before the nighttime temperature hits 50. In the winter they live in our bedroom (our cat eats them if they are accessible) and our offices at work.

Blue Bayoue, what kind of Mangoes are you growing? How big are they? I have been thinking of growing them but have not seen any success stories for these parts.
I have too many plants and little space in my balcony where I grow a full fledged flower garden. So I rotate the houseplants so the ones that can really benefit from outdoor exposure can get a couple of months each.

I have schefflera, dracena, anthurium, Christmas cactus outside. Succulents too. Some get morning sun, shade the rest of the day. CCs get dappled sun. If it gets in the 100 degree zone, I just hose the patio where they sit because it is arid here. As for the cactus and succulents, I have a patio umbrella set up over them. They get very bright light all day and occasionally direct sun as it moves overhead.