You can probably use this if in USA

[TZ -OH6]

Big maps for last frost date and total frost free days

https://www.ncdc.noaa.gov/oa/climate/freezefrost/frostfreemaps.html

Too bad they don't have zone numbers. Are Sunset growing zones similar to these?

[cynthia_h]

Yes, Sunset climate zones are similar to these: squirrelly lines going every which way, following local valleys, dales, elevation zones, river drainages, etc.

Great map!

Cynthia H.
Sunset Zone 17, USDA Zone 9

[DoubleDogFarm]

My place is a blob as usual.

Eric

[gixxerific]

I hate to say it but I have a feeling this spring is going to cooler that the ones we have had lately so be careful. I actually think this trend will be going on for years to come. The last 15 years we had a warming trend it is looking to be going the other way. La nina and the cold Atlantic waters among other factors are to blame.

[applestar]

Ha! There's a cold region blob in southern NJ in the 28°F map! Looks like it follows the shape of the Pine Barrens.

[rainbowgardener]

I hate to say it but I have a feeling this spring is going to cooler that the ones we have had lately so be careful. I actually think this trend will be going on for years to come. The last 15 years we had a warming trend it is looking to be going the other way. La nina and the cold Atlantic waters among other factors are to blame.

can you give any citation for this info? So far in my area after an unusually cold and snowy winter, we are having a quick warm up and what looks like maybe an early spring coming. Farmer's Almanac for my area predicts Mar about average temps, 1.5" less than average precipitation ( I REALLY hope we don't have another drought year coming up!).

Since you mentioned it, I looked up the noaa forecast. It does mention the La Nina effects, but it's a bit technical and very variable throughout different parts of the country. Here's some excerpts:

HE TEMPERATURE OUTLOOK FOR MAM 2011 REFLECTS TYPICAL SPRING LA NINA CONDITIONS AND FAVORS BELOW AVERAGE TEMPERATURES OVER CENTRAL AND SOUTHERN ALASKA, ALONG THE NORTHERN TIER OF THE CONUS FROM WASHINGTON AND OREGON EASTWARD ACROSS THE NORTHERN ROCKIES TO THE WESTERN GREAT LAKES REGION. THE CHANCES FOR ABOVE AVERAGE MEAN TEMPERATURES ARE ENHANCED FROM THE INTERIOR SOUTHWEST AND SOUTHERN ROCKIES TO THE CENTRAL GULF COAST STATES. ...

INCREASES THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES AND DRIER THAN AVERAGE CONDITIONS IN THE SOUTHERN PART OF THE COUNTRY, AND BELOW NORMAL TEMPERATURES AND WETTER THAN MEDIAN CONDITIONS IN THE INTERIOR NORTHWEST. ... AND INCREASED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ACROSS THE INTERIOR SOUTHWEST. (I'm not in the South or the NW or the SW, so what does that mean for me?)

(Longer range) OUTLOOKS FOR MJJ 2011 THROUGH MAM
2012 PRIMARILY REFLECT DECADAL OR LONGER VARIABILITY IN THE LONG TERM CLIMATE STATE FAVORING ABOVE NORMAL TEMPERATURES FOR MUCH OF THE WEST. IN THE LATER LEADS, THE LONGER-TERM TRENDS TILT THE ODDS SLIGHTLY IN FAVOR OF ABOVE NORMAL
TEMPERATURES FOR NEW ENGLAND AND THE GREAT LAKES REGION.

You can read the rest of it here:
https://www.cpc.ncep.noaa.gov/products/predictions/90day/fxus05.html

So what I get from this is that we are having a La Nina spring, which could mean cooler temps for parts of the country and warmer for other parts. By summer it is looking like warmer than normal for much of the country.

[gixxerific]

RBG I am only going by the lead weatherman on my local news. He did his spring long range forecast last night. Normally he is right on though he did goof on the forecast for Jan which is rare. I can't really explain it too much. This guy is as much of an enthusiast about weather like you are about gardening so I trust him, though weather is unpredictable at times, especially here in St Louis area. He is in with the National weather service and devotes his life to weather and all it's anomaly's.

If you would like you could view it [url=https://www.fox2now.com/news/ktvi-dave-murray-2011-spring-forecast-022411,0,2814654.story]here[/url]. I believe he starts talking about this changing trend near the middle.

[DoubleDogFarm]

HE TEMPERATURE OUTLOOK FOR MAM 2011 REFLECTS TYPICAL SPRING LA NINA CONDITIONS AND FAVORS BELOW AVERAGE TEMPERATURES OVER CENTRAL AND SOUTHERN ALASKA, ALONG THE NORTHERN TIER OF THE CONUS FROM WASHINGTON AND OREGON EASTWARD ACROSS THE NORTHERN ROCKIES TO THE WESTERN GREAT LAKES REGION. THE
CHANCES FOR ABOVE AVERAGE MEAN TEMPERATURES ARE ENHANCED FROM THE INTERIOR SOUTHWEST AND SOUTHERN ROCKIES TO THE CENTRAL GULF COAST STATES. ...

INCREASES THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES AND DRIER THAN AVERAGE CONDITIONS IN THE SOUTHERN PART OF THE COUNTRY, AND BELOW NORMAL TEMPERATURES AND WETTER THAN MEDIAN CONDITIONS IN THE INTERIOR NORTHWEST. ... AND INCREASED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES
ACROSS THE INTERIOR SOUTHWEST. (I'm not in the South or the NW or the SW, so what does that mean for me?)

Rainbow, I just heard these exact words this morning on a Seattle radio station. Sounds like below normal temps for the next three months.

Eric

[applestar]

Where's the reference to Atlantic coastal areas and mid-Atlantic region in particular!

Eric, sounds like your welded hoops and poly tunnels are going to see a lot of use. I definitely want to experiment with season extenders.

[tk421storm]

Jease NOAA, you don't need to shout, I can hear you just fine.

HE TEMPERATURE OUTLOOK FOR MAM 2011 REFLECTS TYPICAL SPRING LA NINA CONDITIONS AND FAVORS BELOW AVERAGE TEMPERATURES OVER CENTRAL AND SOUTHERN ALASKA, ALONG THE NORTHERN TIER OF THE CONUS FROM WASHINGTON AND OREGON EASTWARD ACROSS THE NORTHERN ROCKIES TO THE WESTERN GREAT LAKES REGION. THE
CHANCES FOR ABOVE AVERAGE MEAN TEMPERATURES ARE ENHANCED FROM THE INTERIOR SOUTHWEST AND SOUTHERN ROCKIES TO THE CENTRAL GULF COAST STATES. ...

INCREASES THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES AND DRIER THAN AVERAGE CONDITIONS IN THE SOUTHERN PART OF THE COUNTRY, AND BELOW NORMAL TEMPERATURES AND WETTER THAN MEDIAN CONDITIONS IN THE INTERIOR NORTHWEST. ... AND INCREASED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES
ACROSS THE INTERIOR SOUTHWEST. (I'm not in the South or the NW or the SW, so what does that mean for me?)

(Longer range) OUTLOOKS FOR MJJ 2011 THROUGH MAM
2012 PRIMARILY REFLECT DECADAL OR LONGER VARIABILITY IN THE LONG TERM CLIMATE STATE FAVORING ABOVE NORMAL TEMPERATURES FOR MUCH OF THE WEST. IN THE LATER LEADS, THE LONGER-TERM TRENDS TILT THE ODDS SLIGHTLY IN FAVOR OF ABOVE NORMAL
TEMPERATURES FOR NEW ENGLAND AND THE GREAT LAKES REGION.

[garden5]

Thanks for the map. That's pretty interesting, but it only goes so far. I've found that the exact dates are different every year so I usually just look at the extended forecast by by last frost date and judge if it would be a good time to plant.

[TZ -OH6]

The map is conservative (90% occurrence before date for frost) so the date is a safe reference to plant starting seeds indoors but if you watch the weather report you might be able to plant out into the garden much earlier.