From Environment Canada: "Our experts on weather and climate have combed through 45 years of weather records, and determined the probabilities based on the following criteria:

-a "white" Christmas is defined as having at least 2 cm of snow on the ground on December 25."

The probability that there will be a white Christmas in Vancouver is 11%.

The probability that there will be a white Christmas in Hamilton is 68%

What type of probability have they used to determine these probabilities?