Great Frost of 1709
The Great Frost (as it was known in England) or Le Grand Hiver (as it was known in France) was an extraordinarily cold winter in Europe in late 1708 and early 1709, and was found to be the coldest European winter during the past 500 years. The severe cold occurred during the time of low sun spot activity known as the Maunder Minimum.
William Derham recorded in Upminster, near London, a low of −12 °C (10 °F) on the night of 5 January 1709, the lowest he had ever measured since he started taking readings in 1697. His contemporaries in the weather observation field in Europe likewise recorded lows down to −15 °C (5 °F). Derham wrote in Philosophical Transactions: "I believe the Frost was greater (if not more universal also) than any other within the Memory of Man."
France was particularly hard hit by the winter, with the subsequent famine estimated to have caused 600,000 deaths by the end of 1710. Because the famine occurred during wartime, there were contemporary nationalist claims that there were no deaths from starvation in the kingdom of France in 1709.
This winter event has drawn the attention of modern day climatologists in the European Union's Millennium Project because they are presently unable to correlate the known causes of cold weather in Europe today with weather patterns documented in 1709. According to Dennis Wheeler, a climatologist at the University of Sunderland: "Something unusual seems to have been happening".
Anecdotal events 
Françoise-Marie de Bourbon, the Duchess of Orleans, is said to have written a letter to her great aunt in Germany describing how she was still shivering from cold and could barely hold her pen despite having a roaring fire next to her, the door shut, and her entire person wrapped in furs. She wrote, "Never in my life have I seen a winter such as this one."
European Union Millennium Project 
One of the key aims of the European Union Millennium Project is climate reconstruction. This objective has gained significance in recent years because scientists are exploring the precise causes for climate variations instead of merely accepting they are within an acceptable historical range. Modern climate models do not appear to be entirely effective for explaining the climate of 1709.
- Pain, Stephanie (7 February 2009), "1709: The year that Europe froze", New Scientist.
- Luterbacher, Jürg; Dietrich, Daniel; Xoplaki, Elena; Grosjean, Martin; Wanner, Heinz (2004), "European Seasonal and Annual Temperature Variability, Trends, and Extremes Since 1500", Science 303 (5663): 1499–1503, doi:10.1126/science.1093877
- Derham, W. (1708/1709), "The History of the Great Frost in the Last Winter 1703 and 1708/9", Philosophical Transactions (1683–1775) 26: 454–478, JSTOR 103288.
- Monahan, W. Gregory (1993), Year of Sorrows: The great famine of 1709 in Lyon, Columbus: Ohio State University Press, pp. 125–153, ISBN 0-8142-0608-5.
- (French) Lachiver, Marcel (1991), Les Années De Misère: La famine au temps du Grand Roi, 1680–1720, Paris: Fayard, pp. 361, 381–382, ISBN 2-213-02799-4.
- Ó Gráda, Cormac & Chevet, Jean-Michel (2002), "Famine and Market in Ancien Régime France", Journal of Economic History 62 (3): 706–733, doi:10.1017/S0022050702001055, PMID 17494233.
- "Millennium European climate", Department of Geography, Masaryk University, January 26, 2009