Inspired by the chart in this blog post: https://neven1.typepad.com/blog/2011/05/piomas-april-2011.html I made an update version of this, because I was curious whether the trend got verified or not: https://i.imgur.com/PV6Xadw.png Well, as it shows the trends aren't as dramatic now. Seems like, because the dataset isn't really big, the 3 full years in a row (2010, 2011, 2012) underperformed strongly and had a big impact on the polynom trendline. Now, with more data available, it looks more like a variation. However, the days until we see an ice free month are counting. It's only a bit later now.