Extending the edge of climate zones

That’s nearly 24 hours a day. Must get boring. :wink:

Actually it’s nice weather for gardening if it’s not windy or raining.

1 Like

We only do about six months a year with sub freezing temperatures. Seems to be enough.

According to one youtuber there is minus 83 degrees F in Siberia slowly coming down into Canada. Said to be the coldest air in 40 years (since 1982). Here in the Northern Great Plains, zone 4, we cannot grow some apples that grow in New York zone 4 because I don’t think they have the Chinook winds that warm things up and start buds to growing. I have seen it around minus 30 F in the middle of March.

1 Like

My zone 4 is very particular as well.

We usually get a meltdown in January, a week in the 50’s it so. That can be often followed by sub zero temperatures next week. Anything stupid enough to drop winter hardiness either drops dead or suffers from a lot of winter kill. Anything borderline loses all it’s fruiting buds.

We also get tree-knocking winds in the winter. Combine that with sub zero temperatures and you end up with something that redefines actual temperature.

Plus our season is super short. A tree can put up with all the above but if it doesn’t ripen fruit by the first week of October it may never get a chance to actually do much. There is a lady in Anchorage with the perfect test for long growth years, filberts. She gets a crop maybe once a decade when everything is perfect; early spring, short rainy season, and late winter. I’ll probably will have the same with hops.

Same situation here. It warms up 3 times typically before the freeze’s actually end. That is the challenge with growing where I live. I have noticed my filbert are already trying to come out of dormancy in January. Hopefully they are just making the catkins

Here May showers bring June flowers… You can’t even dig a hole in the ground early May because it is still frozen.

I find it fascinating to watch native birches shedding leaves mid September, when most of my apple trees are as green as ever still working on ripening fruit. The native birch are obviously perfectly acclimated to Alaska, they know that is better to err on the side of safety and go to bed early.

The map posted by fruitnut only spans 3.5 months, not even a full dormant season.
Perhaps the map was intended for season-to-date chill hours and was updated weekly.

The temperatures that swincher posted are typical of near-continuous chill-hour periods in the PNW, but we do not have 142 such days for a 3400 total!

But under the Utah Method you’d count as 0.5 units any hours between 49 and 54°, and we get a LOT of those. Presumably that’s the method used to reach 3400+ units. It also counts up to 48° as 1.0 units instead of 45°.

lots of chill hours but I’m eastern Washington and our summers are dry as a bone and up to 110F. high desert, 2k elevation, icy windy winter, hot dry summer, just extreme. plus “silty” soil, it takes a lot to get it to produce. they say we’re zone 6 but a lot of things aren’t hardy enough for the real cold here, the extremes, or for the real heat- tropical stuff or desert stuff love summer and hates our winter, zone 5 or 6a stuff gets through the winter and gets burned in summer.

rough to plan. unpredictable and we don’t get long spring or autumn. no transition time really

1 Like

So with the Utah Banana Belt model, Portland has 119 dates with an average high temperature of <=54. None of those days have an average low temperature <32. So those days total 2856 hours (minus hundreds of 0.5 units). Scraps of other days will get you to 3400, but many of those will occur before leaf loss and after leaf bud.

Also, the (edit: average) annual low temperature for Portland over the most 30 recent complete years puts us in Zone 9a. Looks like winter 2023 will have a low of +20°F.

Portland OR has had many temps under 20F over the last 30 years.
Do you mean the average annual low?

The region where i am compared with Portland…any insights?
My latitude its more like the same as Mount Shasta but i use portland as reference.
My distance to the sea its like from Burnt Ranch to Arcata.
My elevation its 400meter facing north

Portland - Latitude: 45.523064
Capturar
This location is classified as Csb
Average annual temperature is 11.3 °C | 52.4 °F.
The annual rainfall is 1267 mm | 49.9 inch of precipitation falls annually.

Porto Portugal - Latitude: 41.0719,
castelo paiva
The climate here is classified as Csb
Average annual temperature is 13.7 °C | 56.6 °F.
The annual rainfall is 1541 mm | 60.7 inch of precipitation falls annually.

Portland

Porto Portugal

That’s how USDA zones are defined, take the absolute low each year for the last 30 years and then average those numbers. Zone 9a doesn’t mean an area never (or even rarely) has temperatures below 20°F, it just means on average the lowest temperature each winter will fall between 20 and 25°F. So when Larry said the annual lows put them in zone 9a, that by definition meant when you take the average of those 30 measurements.

For example, somewhere that had an annual minimum of 18°F on 20 of the last 30 years, but 28°F on the other ten years would be zone 9a (average annual low of 21.3°F). This is one reason USDA zones aren’t a good way to know how cold it can get in a “test” year, they are just a rough estimate of how cold it “usually” gets each year.

That’s why old timers here don’t talk about USDA zones and reference ‘test years’, how a particular variety handled them. It seems anybody that was here in 1989 remembers that year, all our 7 USDA zones felt it (from 2 months is winter night Barrow to zone 7 in the lower panhandle rain forest).

Reading reports from a lot of the experimental farms you get a lot of data on what was planted, how they were doing for several years, and the most important bit; what happened when the test year came. Often it is not pretty but the survivors can then be officially added to the rosters of the hardy ones.

If you want to know what is not suitable for Alaska, in the spring just drop by Lowes or Home Depot here, their abused tree lots are full of trees that stand little chance to make it. This is the result of it being easier to sell something with a name people recognize than something that will actually work.

1 Like

I know how USDA zones are calculated. I did not ask a question about zones.
Someone stated specifically that Portland had not had any days below 20 for many years. That statement was not correct, so I asked if they meant the average was not below 20. It may be that the person who made that statement was confused about how zones are calculated, but the statement has been removed and my question was not answered.

castanea: Yes, I meant the average of the annual low temperatures. No confusion, just a simple omission of one important word.

Heldervalente: The only thing that stands out from eyeing the graph and stats is your somewhat wetter and more humid summers.

If the graphs on the right are average daily temps superimposed with record averages, the Portland graph shows a wider range of temperatures, indicating a more continental influence even though Portland is only 75 miles from the Pacific Ocean.

The above numbers for Portland are off; 1938-2022 average temperature is 53.93 and average annual rainfall is 36.88". The elevation of weather station KPDX is under 10 meters.

1 Like

My point was about analog climates and looking to understand more how portland is similar to my place.

I would like to know if in such place the fruits people grow are the same to where i am.
For example, is anyone growing eugenias or even anonas combined with cherry trees and chestnuts.

I agree that conditions in Portland are a bit more extreme than where i live but latitude its not exactly the same also, and we also have to consider elevation, orientation and distance to the sea, and eventualy even wind direction, but that is problably the same also.

I used portland as a reference since at latitude 41 at similar conditions i dont find any big town.

I didn’t make any comments about your post.

This graphs and diagrams are also just for reference , at my place i get maybe 5 days of temperature above 40C 100F

Dont know if that would happen in Portland, are you from there?

I have never lived in Portland but am very familiar with it.
Portland is a little warmer in summer than your area. Your area should be fine for many types of fruit and nut trees.