Characterizing Spatiotemporal Trends of Meteorological Extremes in Southern Ontario, Canada

Extreme meteorological conditions are changing in the twentieth century, with potentially severe environmental implications. We explored the changes in these extreme conditions and found seasonal signatures in extreme monthly values of air and dew point temperature and low relative humidity, spatial signatures in those of wind speed and high relative humidity, and no distinct patterns in those of precipitation from 1950–2020 in southern Ontario using the Mann–Kendall trend test and Theil–Sen estimator. We found a minimal role of four large-scale phenomena—Arctic Oscillation, North Atlantic Oscillation, El Niño–Southern Oscillation, and Pacific Decadal Oscillation—in the temporal trends using Bayesian Generalized Extreme Value and Poisson regression models. Warming temperature extremes in the colder months imply changes in ecological phenology. Our findings also suggest that there are fewer extreme cold conditions in colder months and more intense plant water loss and thermal discomfort in warmer months.M.Sc