My growing zone

[JordanNL]

I got bored and got all the anual lows at the St John's airport (cooler then me by 3-5 C). There was 67 years worth and the average anual minimum of -17.5C, isnt that a zone 7a? Veseys say im a 5b?


Heres the data I used. 1969s min. was -11.7C!
http://www.climate.weatheroffice.gc.ca/ ... 9&cmdB1=Go

[Cameron_z6a_N.S.]

From my understanding, it's not the average cold temps, but the lowest. I say that I'm in a zone 6 a/b because the coldest that my location has EVER experienced was -23 C. That being said, I'm far from an expert on this kind of thing I think someone like Paul would have a lot more knowledge on zones !

[Paul Ont]

The USDA growing zone is simply an average of the coldest extreme minimum temperature recorded each year. For example: If I had extreme lows of 0C, -10C, and -20C; my average low would be (0+10+20/3 = -10C, which put me in zone 8a or some such thing. This example also serves to highlight the absurdity of the whole system... it's in no way perfect, but it is, IMO, the best guideline that we have. For what we all want to do we also need to consider frost dates, length of time below freezing, summer heat, precipitation, etc, etc.

Jordan- it looks like your right on the edge of zone 7a (-17.5C is 0.5f), based on a long term sample. Did you include the most recent years in your assessment?

Cameron- I did the zone data for most of Nova Scotia back in 2003/4 or so. If I recall correctly the peninsula of Halifax was 6b, while the surrounding area (including Shearwater and Halifax international) was 6a. I recall talking to John Weagle (HFX seed co.) and, check the record now, he said that the year 1993 was devastating for the city since it hit -26C and stayed below -20C for a few days (It hit -28C at the airport on that date, which I know is colder than the city proper: http://www.climate.weatheroffice.gc.ca/ ... StnId=6358&)

[JordanNL]

Paul,

i got all the data from 1942 - 2009. I know most people would not believe anywhere in NL was z7 but i had to prove it to myself.
We got down to -23.8 like 4 times since 1942, we havent seen -20 since 1994...this is airport data (colder then St Johns West).