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by Anura Guruge

Yesterday was ice-out on Winnipesaukee.

Historic ice-out data going back to 1887 is available at winnipesaukee.com. So that is 127 years worth of ice-out dates.

I, for the first time this year, had a couple of hours off! I am waiting for Amazon to publish another Kindle book. So, I wanted to indulge myself while I waited (patiently) and given that I am strange crunching data is an indulgence.

So, I did some quick analysis. One thing I quickly noticed is that people don’t pay enough attention to LEAP YEARS. In terms of days into the year, March 23 & March 24 are both 82 days in — depending on whether it is a leap-year or not. So to say that last year was the earliest ice-out is wrong in a way.

I copied and pasted, did some concatenations and replaces, used (the now unsupported but still available) =DATEDIF Excel function and =WEEKDAY and voilà. [No, I never type in data.] Yes, I had to hand calculate the 13 pre-1900 years since Excel dates only start as of 1900 — but I used the Windows 7 calculator that can calculate dates going back to 1500 and one of my perpetual calendars. So, I ended up with a sortable Excel spreadsheet — which looked like this, after I had sorted it by data distribution. All calculations are based on days into the year, starting January 1 of each year.

Click to ENLARGE. This was towards the end when I was calculating date distribution.

Ice out dates over the last 127 years. Click to ENLARGE.

The day of the week that ice-out has occurred — Thursdays the most prevalent. Click to ENLARGE.

Distribution of ice-out day across a 51-day spread between March 23 and May 12. Click to ENLARGE.