garden zone??

Does anyone know what gardening zone I'm in-I live in El Dorado Hills, CA and I've looked it up and keep getting different results. I'm getting zone 8 and zone 9. I'm 30 minutes east of Sacramento, CA. I'd appreciate any help! Thanks in advance!!

It's probably going to depend on your elevation--I think Sacramento is in 9a so if you're at the same elevation then that's probably what you are as well, but if you're at a little higher elevation you may be getting towards 8b. I actually find Sunset's climate zones much more useful--if you don't already have it, I'd highly recommend picking up a copy of the Sunset Western Garden book. You can find your Sunset zone in there, plus it has lists of plants and what Sunset zones they do well in. I've found that our winters come with enough cold nights that there are some plants that are supposed to be hardy to zone 9 or even zone 8 that won't make it here, but I've rarely had trouble with things that were supposed to work in my Sunset zone.

I've been getting conflicting results too, and just yesterday was reading about conflicting zone maps prepared at various times; I will paste in some of my notes:

United States National Arboretum map issued 1990, for data 1974 thru 1986:
http://www.usna.usda.gov/Hardzone/ushzmap.html and there is a clickable link on wikipedia article “hardiness zone”. Shows plant survival in an “average’ winter. But non-coastal areas can have a devastating deviation from the average. The 1990 map showed colder temps than the 1960 map, because of very cold winters in 1974 to 1986 period.

American horticultural Society, AHS, in 2003 did a prelim draft of a new USDA map, using data collected from 1986 to 2002, which was a period of warmer winters than the 1974 to 1986 period, thus many areas were moved a half-zone warmer than the 1990 map. Shows finer detail, e.g. urban heat islands for downtown areas of some zities, but it eliminated the half-zone delineations, criticized by horticulturists and gardeners. The usda rejected the AHS 2003 draft map.

Garden Rant says: The usda rejected the revised zone map it commissioned the AHS to do. Then the map was tweaked a bit and released by the Arbor Day Foundation. The the USDA denied the new map was rejected for polical reasons. Now the usda is about ready to release a revision they do approve of, as reported in the Daily Climate. In that article, Tony Avent is quoted criticizing the rejected map because it moved the zones too far southward, e.g. moving Chicago from Zone 5b to zone 6. He said in 2004 Chicago had a winter down to -21, and Zone 6 plants would have died. Then people give up gardening, the worst nightmare of the nursery business.. . . comments . . . .
zone map decisions affected by commercial interests of nurseries and commercial growers,
zone map decisions affected by the politics surrounding the issue of “global warming”

If you look at weather.com for your zip code, then look at "monthly view", down at the bottom you'll see averages, you can uncheck the boxes for averages, and check the boxes for record lows, then you'll know your record low. Then you can use the "guide" to the zones to see which zone that specific record low would be.

for example, record low for my zip was minus 20 in 1994.
Map guide indicates:
5a -15 down to -20
5b -10 down to -15
6a -5 down to -10

Some maps tell me I am Zone 5, some say 6a, some say 5b/6a. But I know I should stick to plants recommended for Zone 5a or 5 if I want to take less risk.

Here's a link to the Sunset Climate Zones for California: http://www.sunset.com/garden/climate-zones/sunset-climate-zones-california-nevada-00400000036331/

When the shooting stops my pile of legs will show lawyers on the bottom, next accountants and finally but still close to the hit list top would be gardening cataglog writers and zone writers. Study the advise of all and just do your thing. In time you will be able to better most of the advisors, perhaps become one of the above and get on my list if I live long enough to see the changes in your discovery items.