Analyzing 116 Years of Ice-out Data
Lake Minnetonka, Minnesota
(Back to Journey North Ice-out Contest)

Lake Minnetonka
Ice-Out Dates


The "scattergram" on the right includes 116 ice-out dates for Lake Minnetonka from 1887 to 2002.
  • Print the scattergram.
  • At first glance, do you see any pattern?
  • Draw a line on the scattergram to show the average ice-out date for Lake Minnetonka. (To find the average, use the ice-out records on this table.)
  • On the scattergram, find the five years when ice-out occurred the EARLIEST.
  • Next, find the five years when ice-out occurred the LATEST.
  • Do you see any patterns?
  • How else might you display the data?
  • People concerned about global warming use ice-out dates as one measure of climate change. Do you see a warming trend, based on data from this lake?