The Meteorological Observations of Jean-François Gaultier, Quebec, Canada: 1742–56

Jean-François Gaultier was a physician in the French colony of Québec in New France from 1742 to 1756. During that period, he recorded daily readings of temperature and observations of the weather, although only the observations for 1742–46, 1747–48, and 1754 have been located to date. Daily instrumental temperature data from Québec for the 1740s provide a glimpse of climate variability in eastern North America, upstream of the North Atlantic. During the 1740s, winters appear to have been milder than during most of the twentieth century with the exception of the 1950s and early 1980s, and summers warmer than those of the twentieth century, with the exception of the 1970s and 1990s. Autumns and springs appear to have been cool relative to the twentieth century, suggesting that, while winters may have been milder, the winter season lasted longer, with a consequently shorter growing season. The cool springs and autumns, combined with warm winters and summers, give these few years in the 1740s annual average temperatures comparable to those averaged over the twentieth century; the annual average temperatures mask marked seasonal differences. There is also some evidence that the climate was drier than in recent times, with fewer precipitation days than during the 1970–2000 period.