One of the best things about not living in NJ anymore. I couldn't leave a ball or a bike outside for any period of time without it getting stolen by some jerk.
I was able to leave my veileds out for much of the year a few years back, when I was living with my parents in rural NC. It's almost as if they "wake up". The sunlight really makes a difference. Just make sure they can get some cover. My veileds were fine in 104 degree heat, but they had an 8x12x8 cage, and could seek cover. Put one in a small cage, with no shade, and they can die in 90 degree heat.
Also, keep them either caged, or under close supervision. Never underestimate how sharp the vision of birds can be.