You don't have to do that. You can plant now.

I've always heard of "two weeks of sweater weather" before planting spring bulbs, so personally, I am going to wait until that happens.
Last year I planted narcissus bulbs in September and they actually sprouted in November. I don't know if it was the warm weather we were having last year. But I learned my lesson.

I've always read that root formation improves winter hardiness. Can't say I've read a scientific report on it.
I alway have bulbs that peak up during warm spells. They stop when it gets cold again. They still flower in the spring.
In any case, you have some flexibility so do it when its convenient. I've even planted as late as January. The worst part about planting late is that the squirrels know when the ground has been disturbed and bother the bulbs.

Thanks for the great info all around. Well, the warm weather is working out b/c I've come to realize that my development's planned "beds" are actually boulders & rocks surrounded by tree roots with some soil in between. So the extra weeks & warm are allowing my time to dig it all up & start over :)
All the Best
Tree