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Last and First Frost for Salt Lake Valley Research Back 40 years

Posted by pcan 7 UT (My Page) on
Mon, Jan 23, 12 at 21:11

This weekend I had some time on my hands. So not only did I track all winter temps that dropped below 10*, going back to 1970, per SL International Weather Data, and found out I am actually a zone 7a per the last 2 decades of temps. I also put a graph together of the first and last frost in Salt Lake Valley going back 40+ years and thought it might be helpful to some of you.

The different color bars indicate decades
The bold black line across each decade indicates the average for that decade
The red line is the running average for the 40 years
The grey shading indicates the 7 days before and after the average frost

Thought you may find it useful, I sure am.


Follow-Up Postings:

RE: Last and First Frost for Salt Lake Valley Research Back 40 ye

thanks for the graph.. i was thinking of that in
light of the new info from usda on revised growing in provo im now in 7b.. wow.. !!
many of my fellow garden enthusiasts have been talking
now what about last/1st frosts..
thanks for this !!!!

RE: Last and First Frost for Salt Lake Valley Research Back 40 ye

  • Posted by abq_bob USDA 8b- 9a / SS 11 (My Page) on
    Wed, Mar 21, 12 at 14:55

I tend to use "marker plants" for zone, before I'd go on temp. values alone. I lived in Albuquerque (zone 7b) for over 10 years, and in Salt Lake for over 25, and I highly doubt one can grow the same things in Salt Lake (or Provo) that easily grow in Albuquerque.

First and last frost dates also make a big difference. My garden in Albuquerque had (at minimum) 4 months longer growing season than my Mother's back in Utah. My usual first killing frost was around Thanksgiving (never had one earlier than Nov 15), and crocus blooming around Valentine's Day, daffs by my birthday in the first week of March (last hard frost usually the first or second week of March). Only had a couple of odd years when we had exceptionally late frosts around April 1 - but even those only killed the most tender of plants.

Stuff I grew as perennials (without any special protection or fussing) in ABQ that I think might be problematic in Salt Lake/Provo Utah; Artichokes, Pineapple sage, bletilla ground orchids, fuzzy kiwi vines, agapanthus, peruvian daffodils, harlequin glorybower tree, rosemary (as a 4' shrub), passion flower vines (incense and cerulea), jasmine vines, lemon verbena, crinums, pistachio trees, desert willow trees (Chilopsis linearis), Mimosa (Albizia julibrissin), Desert Bird of Paradise (these grow wild all over ABQ - Caesalpinia gilliesii), etc.

And when you have 20-30+ foot yuccas all over town, as in the link below, let me know.

I don't mean to be a total "rain cloud" - I just offer this as a "procede with caution" tale.

Here is a link that might be useful: Yuccas in ABQ

RE: Last and First Frost for Salt Lake Valley Research Back 40 ye

On the new Zone map Albuquerque shows as zone 8a. It seems even before the zone change and now they ahve always been a zone warmer than us. Which makes sense why you can't grow the same things here as you can there. While Salt Lake valley's temps are mild we do have a shorter growing season. I think that is due to elevation and latitude.

BTW, my neighbors have a beautiful Mimosa tree and I planted one this year :)

plant zone

I was just looking at the plants you listed and they are for the most part zoned for USDA zone 8 and above except the Mimosa which is a zone 7.

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