Daylilies do not need any length of winter dormancy - they do not need to go dormant.
I have tested a number of different cultivars that were supposed to "need" dormancy and none so far have needed to be dormant for any obvious reason.
I have done tests in which the daylily was not allowed to go dormant. Those daylilies grew and flowered perfectly normally. I have done tests in which the daylily was allowed to go dormant and I then broke its dormancy by providing the plants with spring conditions in autumn. They broke dormancy and grew normally.
If you have a daylily that has gone winter dormant and you would like it to start growing and flower, for example, inside during the winter, you need to provide it with (1) warm spring-like temperatures (a house temperature of 72F or 22C will do). You also need to provide it with (2) long days (16 hours of light and 8 hours of dark). Most importantly, you need to provide it with the normal spring intensity of sunlight (or as close to normal as possible - meaning high light intensities). I place a normal household (800 lumen) led light bulb a couple of inches away from the daylily bud. It may take a few days (about a week or so) before the bud starts into growth. The led light bulb can then be removed and replaced with grow lights, fluorescent lights, etc. at reasonable heights from the daylily leaves - daylilies are high light requiring plants rather than low light.
Daylilies (registered as early season blooming) that I have brought inside at the beginning of September (here) before they go dormant flower in December. They flowered in July outside. They grow inside all winter and I put them back outside in late spring or early summer where they then flower. Daylilies with later flowering times flower inside in January or February or later, etc.
If a daylily goes dormant then how long it takes to flower inside is delayed by the amount of time it is allowed to remain dormant and the amount of time it requires to break its dormancy.
