i notice mine are coming back as well..

mine seeem to be doing well considering we have had some frost already

This is my second year with nasturtiums and this happens with most but not all. I feel like the really special single colored (mahogony, salmon, pale yellow etc) dont but that what are likely the older varieties zoom back when it gets cooler. I tried planting more in the middle of August to take advantage of this but I think the plants wont get big enough to flower before they are knocked down by serious frosts. Next year I will try doing this earlier with seed I collect now. This is a nice feature of nasturtiums and a good reason to keep watering them when they are suffering from the heat. I had them flowering for me here well into November last year. They were one of the last to pack it in.

I was growing jewel mix and peach melba in pots this year.
When it got so hot, humid and dry in MA over he summer, it was just impossible to keep up with the watering. Was going to give up on them when hubby moved them to mostly shade becase they just "looked to pathetic in the hot humid sun". My thought was, it won't matter now, cause they need full sun, so the package said. To my surprise, they perked up within a few days and bloomed all summer with just 3 hours of early morning sun, from about 8-11am.
When it started to cool down in mid Sept. I moved them back into full sun again and of course they have sure had plenty of water. They look great now and did all summer

Mine were a pretty variety called apricot trifle. They didn't look like the photo in the catalog ( a salmon pink-peach shade) but they were really pretty, more like a soft peachy-orange and just loaded with flowers. Until the really hot, dry weather. Now, they are nice and green and reviving well. But, I doubt if they will flower again, tonight we are supposed to get a frost.

Yeah and I was told hot was what they liked! HA! Not here anyways!
I had 'Scarlet Gleam'...they went great guns early on thru June..vining all over. Then July and August came along with our 90+ temps, low humidity and they grew uglier by the day...Then as as soon as cooler fall temps arrived off they went again as beautiful as ever :)

Vera

Mine are still blooming here in Cincinnati, and we have had several frosts. I'm getting lots of seeds for next year

I've read that nasturtuims do not like hot weather and that they will return with cooler temps...And if they were in the shade, they did lots better. From my experience that is what happened with mine...just 2 cents worth...