When should I plant tulip bulbs?

You should plant them in the fall, before the first frost, ,just because it will be easier to plant them if the ground is not frozen.The tulips will grow in the spring.

When should I plant tulip bulbs?
THE FALL
Reply:mid september in severe early frost winter areas. and anytime up til early december in mild winter areas where the ground does not freeze hard til dec or january. bulbs need a good 14 to 16 weeks of dormant chill in order to bloom well.
Reply:Plant tulips in October through late November, when the soil has cooled to below 50°F. This temperature is essential to root development. Tulips will grow in most soil types, but if your soil is particularly sandy or heavy clay you would greatly benefit from loosening the soil and the addition of organic material such as compost, peat moss, etc. A few handfuls of pea gravel at the very bottom of the planting hole would also be beneficial as tulips demand excellent drainage.