How to Have Fun with the New Hardiness Map

– Posted in: How-to, Recommended Links

Since I just got done telling you what the new USDA Hardiness Map is not good for, I thought I should at least show you how to have some fun with it. Okay, not rolling on the floor laughing fun. Probably more like, “what can I do instead of my taxes?” fun. But, hey, fun is defined by the alternative. The USDA says its new map “enables viewers to examine plant hardiness zones at a much finer scale than ever before.” We’re going to see just how fine we can get it.

Find Your Coordinates

In your own mind, choose a place whose hardiness you want to know. No, you don’t have to tell anybody, but let’s just assume it is your own garden. First, you need to know the latitude and longitude of that place. If you don’t happen to have it memorized, go to Google Maps and type in the street address. Right-click on the location marker and choose Drop LatLng Marker from the little menu that pops up. Write down the coordinates (low tech), or do the next step in a new browser window (low stress), or go ahead, memorize the coordinates (nerd!). Suit yourself. If you have some easier, better way to get the coordinates, you can tell me in the comments.

Enter Your Zip Code

Enter your zip codeNext, visit the new hardiness map site. Make sure you’re on the interactive map tab. Unfortunately, there’s no way to directly enter the map coordinates we obtained in step one. We have to achieve our goal through a rather kludgy process. Enter the zip code for your chosen location in the box provided, right under the words Interactive Map in the upper left corner. (If you don’t know your zip code, look it up here.) Click the Locate button, if you haven’t already figured that out.

Zoom In With the Best Base Map

Now you are in the general area. But you can get much closer. You can move the map around by clicking on it and holding down the mouse button as you move it around. Slide the zoom level all the way to the top so you are zoomed in as close as possible.

Choose the basemap and the transparency level

Choose the basemap and the transparency level

Now, slide the Zone Color Transparency all the way to 100. This has the effect of removing the zone colors, revealing the map underneath. Please note you can change the base map to terrain, road map, or satellite image. Use whichever helps you pinpoint your location best. I couldn’t zoom in close enough on my location to see my rural road, so terrain actually worked better for me.

Click Marks the Spot

The moment of truth has arrived. Click on the spot that you believe is your chosen location. A little box will pop up, informing you of the zone, the average temperature of that spot, the temperature range, and the latitude and longitude of the place that you clicked on. This is how you determine how accurately you clicked on the exact, precise location you desired. In my case, I was .01078 off in latitude and .00470 off in longitude, so I feel like I got it close enough. At my new house, I am Zone 5b, the average winter low is -13F (-25C), and the range is -15F to -10F (-26.1C to -23.3C). At my old house, I could see the road on the interactive zone map when I was all the way zoomed in, and I was only off by .00096 in latitude and .00068 in longitude. Pretty much right on the mark. Here at the old place, it is also Zone 5b, the average temp. is -13.9F, and the range is exactly the same. Keep in mind these are interpolated results. I have found that if you click around in the same general location, you get a different average temp every time. Whether it really means anything is another story. But, hey, it beats doing taxes, right?

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

If winter is slumber and spring is birth, and summer is life, then autumn rounds out to be reflection. It’s a time of year when the leaves are down and the harvest is in and the perennials are gone. Mother Earth just closed up the drapes on another year and it’s time to reflect on what’s come before.

~Mitchell Burgess in Northern Exposure

Comments on this entry are closed.

Alternative Eden March 16, 2012, 12:40 pm

As well as updating the zones for the US there is to be an updated zone guide for the UK. With info on plants being more international, its really good to get more standardised info!


Julie February 15, 2012, 10:01 pm

I was so eager to play with the new hardiness map–and nothing changed for me. Still, we have such a strange little microclimate in our garden…I need a microclimate map just for our yard! Thanks for sharing!

Kathy Purdy February 15, 2012, 11:07 pm

You will probably map it in your mind, Julie. Thanks for commenting.

Debra @ Gardens Inspired February 15, 2012, 11:00 am

I love it when I discover a new gardening blog to enjoy. I loved this post and also garden in a cold-ish climate; but you win. Our Zone just changed from 5b to 6a.

Thank you for the tutorial – I enjoyed it very much. ~Debra, Gardens Inspired

Kathy Purdy February 15, 2012, 11:08 am

Thanks for stopping by, Debra. Glad to meet another gardener.

Debra February 12, 2012, 11:45 pm

Thanks for this tutorial, Kathy. I feel like we’ve been waiting forever for this new map!
Glad to find out what it’s good for!
xo debra

Deborah B February 10, 2012, 5:45 pm

I guess you’re going to have to change your USDA Hardiness Zone in your “About Kathy Purdy” blurb… and in another 10 or 15 years you’ll need to change your blog title!

Kathy Purdy February 10, 2012, 7:24 pm

Cold is relative, and I think northern gardens will always be colder than southern gardens, even if it is warmer everywhere. I have thought about changing my zone in the blurb, but it still feels like a zone 4 garden for much of the year. True, it hasn’t gotten quite as cold in the winter for several years, but the plants still get killed during mud season, even if they make it through the winter.

Aagaard Farms February 9, 2012, 11:48 am

Kathy: I’d like to nominate you for a Versatile Blogger Award. Details will be up soon at my blog at I enjoy your stuff!

commonweeder February 7, 2012, 8:27 am

I left my husband to do the taxes while I had some fun. Great post.

Yael February 7, 2012, 2:28 am


Very neat. I hadn’t seen this yet. I had a general knowledge that I am in zone 8 (maybe zone 7 up on our hill). But now with this map, I find a refined description of my zone as 8B, with an average low of 16.8 F. Clicking on the map, I was pretty accurate with my location, so I am good with what I found out. Cool.


Lynn February 5, 2012, 11:46 pm

Anything to avoid taxes! Nice work!