1. May 9
2. April 23
3. April 28
4. May 10
5. April 27
6. April 21


1. May 1
2. April 30
3. April 18
4. April 20
5. April 26
6. May 6


The easiest technique to choose an ice-out date is to open a calendar to April/May and throw a dart. However, if you want to improve your chances of winning you might review the ice-out facts and throw a dart at a smaller number of dates. Or you can review the same ice-out data and look at the dates to pick/avoid (shown above) and choose a date based on the theory that the actual ice-out percentages will, over time, match the normal (Bell) curve. This is happening with each passing year but it's certainly not foolproof for any given year, although the above dates improve your chances over the dart technique. Are you wondering why May 8, 9 and 10th are in the top picks?

Answer: Over 10% of the ice-outs have occurred after May 10th. There is only 1 ice-out date for May 8,9,10th combined, around 1%. This creates a hole in the distribution. There should be 3-4 "ice-outs" on these dates to fill in the hole and match the Bell curve shape.


In 2016, the ice went out on April 25th. Since this date is close to the average ice out date it only moved the ice out average by 1 hour and 17 minutes towards an April 28th average. The DNR reports the average ice out date as April 29th. If the Iceman's database average is rounded up, the average is April 29th too.

Three questions from last year's chatter were raised. First, which monthly average high temperature, average low temperature, or snow fall correlates best to the ice out date? Second, which month's weather conditions best correlates to the ice out date, and third, is there a monthly cumulative correlation improvement effect on predicting the ice out date?

I used to include the month of November but that month contributed very little to the ice out date so I dropped it. The month of May is unique (less variability) because the range in ice out dates is 23 days compared with 30/31 days for the other months. So the May weather conditions have very good correlation to a May ice out date (R=60 to 70%). Here are the results of running statistical correlation tests for the months of December to April.

1. The top three monthly weather elements that correlate best to the ice out date are: April High Temp (R=56.33%); March High Temp (R=55.87%); and April Snow (R=52.07%). The bottom three monthly weather elements that do not correlate well to the ice out date are: Feb. Snow (R=1.35%); Jan. Snow (R=12.85%) and Jan. High Temp (R=23.29%).

2. The weather conditions of April correlates (64.78%) best to the ice out date. The weather conditions in March have a 58.03% correlation factor. The weather conditions in January and February have correlation factors in the low 30 percents.

3. Yes, there is a monthly cumulative correlation improvement effect on predicting the ice out date. Here are the numbers:

Dec. and Jan.
Dec., Jan., and Feb.
Dec., Jan., Feb., and Mar.
Dec., Jan., Feb., Mar., and Apr.

Using all of the data enhances your chances of winning the ice out contest.

Good Luck!

© Iceman - January 2017