Frost days
At a recent meeting of our local Seed Savers group, we talked a little about the various climate types across the area. In an effort to visualize this, ewe have analyzed our weather station data starlightcascade.ca/weather for two data points: light frost as -1C and heavy frost as -3C
Frost days at StarlightCascade Gardens just outside Yarker Ontario
Two types, light frost low temperature of -1C and heavy frost low temperature of -3C.
These define the first day of the fall with frost to the last day in the spring with frost, those temperatures which may kill off unprotected plants.
A heavy frost is more likely to be a killing frost, whereas some plants may survive a light frost.
The data is from our weather station
http://starlightcascade.ca/weather/
Light Frost (low temp -1C)
2002 Oct 21 (-3) to 2003 Apr 30 (-1) = 191 “days of light frost”
2003 Oct 23 (-2) to 2004 May 08 (-2) = 197 “days of light frost”
2004 Oct 11 (-1) to 2005 May 17 (-1) = 218 “days of light frost”
2005 Oct 20 (-1) to 2006 no data
2006 no data
2007 Oct 12 (-2) to 2008 May 05 (-2) = 205 “days of light frost”
2008 Oct 06 (-2) to 2009 May 13 (-1) = 219 “days of light frost”
2009 Sep 19 (-1) to 2010 June 13 (-2)= 268 “days of light frost”
2010 Oct 10 (-2) to 2011 pending
Heavy Frost (low temp -3C)
2002 Oct 31 (-3) to 2003 Apr 24 (-3) = 176 “days of heavy frost”
2003 Nov 08 (-6) to 2004 Apr 16 (-4) = 160 “days of heavy frost”
2004 Nov 03 (-4) to 2005 Mar 13 (-3) = 131 “days of heavy frost”
2005 Oct 21 (-4) to 2006 no data
2006 no data
2007 Oct 13 (-3) to 2008 Apr 30 (-3) = 199 “days of heavy frost”
2008 Oct 07 (-4) to 2009 Apr 17 (-5) = 192 “days of heavy frost”
2009 Oct 12 (-5) to 2010 June 11 (-4)= 242 “days of heavy frost”
2010 Nov 01 (-3) to 2011 pending
A closer look at the data shows more outliers in recent years, that is, the majority of the data readings are getting warmer, but there are more abnomalies later in the summer. We interpret these as a more energetic and chaotic climate with more variability.