The borders of the zones done in shades of yellow are murder to make out. They should draw those in with a darker edging.

Yes, I agree that it can be kind of hard to tell the difference between some of the zones, since the colors are so similar. It took me a little bit to figure out if I was in zone 7a or 6b.

The zip code search did put me in the right zone, so that part can be useful.

Maybe my color comparative skills are off, but it seems that the color key colors don't exactly match the colors on the maps. I thought I was just loosing my mind (and that's yet to be determined), but, even after a very close look, it still seems like that's the case (especially on the large-version maps).

The colors on this new map are very similar. The USDA should have used clearly different colors for the different zones, so there would be no confusion. I guess they wanted it to be color coordinated for eye appeal, which is silly, because I'm not planting the map.
Anyway, I am looking at Tennessee right now. Franklin County is mostly zone 7a, but there is a long blotch of zone 7b running from the SW corner up towards the NE corner of the county. Shelby County is really hard to read. It is all zone 7b except for part of the extreme SW corner, which is zone 8a. That is the only zone 8a I see in the entire state of TN, and the city name "Memphis" is partially covering it.
I have fairly young eyes, but if an older person (no disrespect intended) looked at this new map, I'm sure it could be very hard to tell these colors apart.
Oh well, what do you expect? The Federal Government made it. lol

Actually on a case-by-case basis I'd say a lot more baloney is encountered coming from the for-profit private sector.

Since the government is supposed to be providing public services (rather than lining pockets) as its main mission one might hope the map gets tuned later to become readable.

Yes, bboy, I would have to agree. The USDA usually contracts these types of things out to private companies, but the USDA still has to approve the final product. I wouldn't think it would be that difficult to edit the colors to make the map readable.
I just finished contacting the USDA via e-mail asking them if they would be willing to edit the colors. I'm sure I'm not the only person who has asked them to make the new map more readable.

Hopefully.

I just received a response from the USDA, and here is what they told me. It makes sense.

Thank you for your inquiry. Selecting 26 colors (13 zones with A and B subdivisions) that can be visually separated was a difficult task. The job was further complicated because we had to select colors that would appear the same in both print (CMYK system of colors) and on screen (RGB system of colors). If you are having trouble viewing colors or matching them to the legend, the ZIP code finder on the web site�s front page or on the interactive map can provide your zone without reference to colors.
We hope this helps.
PHZM Help Team

Just changed my profile from 6a to 6b, but the change was borderline (pun intended). I liked being able to click on my state and that helped this old person's eyes see the line better.

Vickie