For example, the coldest December 1 ever in downtown Toronto was in 1875. The overnight low that day was -18.9C, and the high was -9.4C. And 27.9 centimetres of snow fell that day too. Ick.
Looking at the records, it's easy to believe that the Earth is getting warmer. Of the ten coldest December 1 days in history, nine of them were in the 19th century, whereas only one of the ten warmest December 1 days was before 1900.
And, thanks to a PHP program I wrote that crunched numbers for me, the evidence for global warming is more obvious when you look at larger samples:
- In the years between 1850 and 1859, the average December highs and lows were -0.7C and -7.6C.
- In the years between 1990 and 1999, the averages were 2.9C and -2.2C.
- The increase has been gradual: the average in the 1930s was 1.3C and -5.0C.
- The coldest temperature recorded in downtown Toronto was -32.8C, on January 10, 1859.
- The coldest 20th century temperature: -30C, on December 29, 1933.
- Most snow in one day: 48.3 centimetres on December 11, 1944.
- Most rain in one day: 98.6 millimetres on July 27, 1897.
- Warmest temperature ever: 40.6C, on July 8, 9 and 10, 1936. (July 1921 had four consecutive days over 36C, and July 1911 had three straight days over 36.7C.)
As I write this, there's high drama taking place in Montreal: the Liberal Party convention is about to announce the results of the second ballot for the party leadership. This is the ballot on which all the delegates are free to vote however they choose, so anything could happen. Whee!