Why isn’t the Arctic ice extent record observed for day 61 16.5, rather than the 16.14 shown on the bottom of the plot? Is one year intentionally ignored for some reason? It really doesn’t make much difference, since the present area is only down about 11% from the max we have observed.
Until about 1986, NSIDC only measured every other day. I wrestle with the idea of using infilled data for the records. But technically there sometimes was no measurement ….
sunshine hours 
Why isn’t the Arctic ice extent record observed for day 61 16.5, rather than the 16.14 shown on the bottom of the plot? Is one year intentionally ignored for some reason? It really doesn’t make much difference, since the present area is only down about 11% from the max we have observed.
Until about 1986, NSIDC only measured every other day. I wrestle with the idea of using infilled data for the records. But technically there sometimes was no measurement ….