Here I can plant squash, including pumpkins around the middle of April. For Halloween pumpkins, I usually hold off till late June, early July so that they ripen in September. Not much use for a Halloween type pumpkin in July.

You should wait till spring because even if your frosts are rare it only takes one to kill the plant. They are VERY frost sensitive. According to NOAA's freeze/frost data the University of Arizona in Tuscon has a 50% chance of frost on Feb. 20th and a 10% chance by Apr 1st, so around the beginning of April would be the earliest you should plant. On the other hand unless you have a particularly large yard you have many more seeds than you will need from that pumpkin so it couldn't hurt to experiment and plant a few now, just don't be shocked if you get a rare frost and it kills the plant. I plant my pumpkins May 15th. I would love to have ripe pumpkins in July! Mine usually start to ripen around mid-August, just in time for the State Fair. This weekend is a sad weekend for me because everyone will be getting rid of their pumpkins till next year.

One final note is that day length is important to squash. Plants grown now won't be as vigorous as ones grown during the summer. However if you can keep off disease and pests as the days shorten your plants will produce more female flowers. I have some ornamental gourds still going and EVERY flower is female.

What do you use your pumpkins for? I got into vegetable gardening this year and am fascinated by anything I can grow. It would be neat to have some pumpkins by next halloween, so sounds like I might want to wait a bit before planting anything. I didn't save all of the seeds, made toasted pumpkin seeds out of most of them. We had one white pumpkin, anyone know if that is a special variety or just a genetic mutation? It smelled like cucumber when you cut into it.

White pumpkins are special varieties. There is probably a dozen or so 'white' pumpkins. I say that because many supposedly white pumpkins can take on a yellow or blue/gray tint. My pumpkins are mostly for decoration. I love having them around at all times of the year. I do eat the squash I grow like butternut. And my gourds (small, colorful, ornamental ones) are also for decoration. I grow those because they are so rewarding (up to ~50 per plant)