Googled farmer's almanac and got the following:

50% probability of frost free after March 1 (at SOUTH PHOENIX, AZ climate station).

Generally Valentine's Day is considered 'safe'. HTH.

Here is a link that might be useful: Farmer's Almanac

The best source can be found by doing a google search of "Last frost date by zip code" and going to the the link at the top of the list.

Here is a link that might be useful: Last frost date by zip code

That's pretty good....here's mine:

Each winter, on average, your risk of frost is from December 13 through February 6.
Almost certainly, however, you will receive frost from January 17 through December 30.

You are almost guaranteed that you will not get frost from March 15 through November 10.

Your frost-free growing season is around 310 days.

- - -
But how many days is my blast furnace-free growing season??

I'm going to be pushing things a bit this year because our winter has been so mild. If the long range forecast looks favorable on February 15th then I will be planting out transplants on February 15th. If the long range forecast is favorable but wrong I may need to cover things once or twice but I'm ready for it.

I found this neat website that shows a map and each region's last frost date

http://www.plantmaps.com/interactive-arizona-last-frost-date-map.php

raimeiken, I think that map is a little optimistic when it comes to Mesa. Though I think/hope its right this year. However we have had a hard freeze several times in the last 5-6 years well past its optimistic last frost date. I like it though because it tells me what I want to hear.lol

Fun maps and discussion! You're all right of course, that this winter feels much more mild than last winter (so far). I still haven't had any frost in my garden--I attribute it to my part of town being fairly steep so cooler air runs downhill rather than settling. My basil is still alive and growing just fine. Even so, I don't usually feel safe until mid-March. Love all these maps and sites though--really fun to see! I hate frost, by the way, LOL.

I really like this map that someone else posted here on the forum once. Interactive Frost Map of Arizona You can zoom in right down to your very street, and see what your average last frost date is. It can vary quite a bit even within a zip code, so this is gives you better information. For my neighborhood, the last expected frost is Feb 21 - Feb 29.

plstqd, thanks for pointing out the zoom-ability. I didn't realize that. Nice.

You're very welcome. I feel a little silly, though, because I didn't realize that raimeiken had posted the exact same map above!

not to worry!

Looks like I will be able to plant early this year. Given the size of my squash seedlings its a good thing too. They either need to move up to 6 inch pots ASAP or be planted.

Note to self.

Start squash, melons and cucumbers two weeks later next year.

Given the long range forecast I will be putting out transplants starting tomorrow.

Wish me luck.