When do the seasons begin and end where you live?

There are three seasonal definitions that I like:
1) The Wawa Seasonal Index (invented by City-Data user wawa1992). It goes like this:

Winter is defined where the mean temperature averages at or below freezing.
Summer is defined where the mean temperature averages 68F/20C or above.
Spring and Fall are defined as the seasons between Winter and Summer.


2) The Zzontar Season Index (invented by user of same name in another forum) defines the seasons as the following:

The last day of Winter is the last date in which the daily maximum temperature does not exceed 0°C.
The last day of Spring is the last date in which the daily minimum temperature drops to 0°C.
The first day of Fall coincides with the first frost after mid summer (after July 16th).
The first day of Winter occurs when the daily maximum temperature does not exceed 0 degrees Celsius for the first time after mid summer.


3) The Glacial Seasonal Index (invented by Yours Truly). It works like this:

Find the coldest and hottest days of the year.
Calculate the mid-mid points. Point X = A/2 + (A+B)/4; Point Y = B/2 + (A+B)/4
The points in the year when the mean temperature crosses these points (X and Y) is the point at which the seasons change.


These definitions don't work for all cases, so you might have to use a different base. For example, most of Canada would not have a summer with the default Wawa, so one might want to use Wawa (0,15) for cooler climates or the Zzontar (10) for warmer climates. The Glacial Seasonal Index will work in all cases outside of the tropics.


For Kamloops, BC:

Wawa:
Winter = November 25th to February 16th = 93 days long
Spring = February 17th to July 2nd = 136 days long
Summer = July 3rd to August 22nd = 51 days long
Fall = August 23rd to November 24th = 94 days long

Zzontar:
Winter = December 17th to January 26th = 41 days
Spring = January 27th to March 24th = 57 days
Summer = March 25th to November 4th = 225 days
Fall = November 5th to December 16th = 42 days

Glacial:
Coldest day of the year = January 9th
Warmest day of the year = July 30th
midpoints = April 20th and October 19th
mid-midpoints = Feb 28, June 9; Sept 8, Nov 29

Winter = November 29th to February 27th = 91 days
Spring = February 28th to June 8th = 101 days
Summer = June 9th to September 7th = 91 days
Fall = September 8th to November 28th = 82 days