A period of severe cold was recorded (comparative temperatures at Lake Superior and Chicago).

The evidence

• “It is a well-ascertained fact that during the colder seasons the lake country is not only relatively, but positively, warmer than places far south of it. The thermometer, during the severe cold of January, 1856, did not fall so low at the coldest, by 10'' to 15° at Lake Superior as at Chicago at the same time. This remark holds true of the changes of all periods of duration, even if continued over a month.”

  1879-history-of-rock-county/04-wisconsin-railroads-commerce-health-statistics.md, PDF p. 229 / book p. 233

  Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.

  Grade A: Found on a page of one of our sources