I'm in the North, latitude 44 degrees 30 minutes North. Most rebloomers will not rebloom here under normal/typical garden conditions.
But to flower a fan must grow; it takes time to rebloom because the basic sequence is grow a number of leaves and then produce a scape; grow a certain number of leaves and then produce a scape, repeat as many times as possible within the growing season in the location.
To get rebloom the fan must grow as fast as it can. Plants grow more quickly when they receive optimum water, optimum sunlight, minimum competition and optimum fertilizer, etc.
I have done this test with several cultivars now. If I grow them normally they do not rebloom; if I mulch them, water them, fertilize them and keep them weeded they rebloom (It takes a year of optimum treatment to get them to a size that allows them to grow, flower and rebloom well). I have managed to take one cultivar that bloomed only once here to three bloom periods, although the usual is just two bloom periods.
Of course, the longer your growing season then the more rounds of rebloom you can have. One way the length of growing seasons is measured is by the number of frost-free days. Another way is by the number of 'growing degree days' (available from the weatherunderground for most locations). My growing season averages between 1800 to 1900 growing degree days per year.
If you have a cultivar that is registered as reblooming in the North and it does not rebloom for you, try mulching it, watering, fertilizing (with a reasonable amount of nitrogen), weeding, dividing it if it is a large clump, growing it in full sun, etc.
Hybridizers tend to grow their introductions under optimum or luxuriant conditions (so they get plenty of increase). Those conditions are also optimum for rebloom.
It is easy to get a rebloomer to a condition in which it cannot rebloom. One way is to simply let it clump up. The more fans in a clump then the more competition for everything vital (resources - water, fertilizer, light, etc.,). Stella de Oro will rebloom here, but not after it becomes a large clump. The better/quicker the daylily can grow the more likely it will rebloom.
I have been told by at least one Florida hybridizer that nearly all daylily cultivars will rebloom in their Florida growing conditions. They do have a long growing season, but they also provide optimum growing conditions for all other aspects and the plants reward them with multiple rounds of growth and bloom.
