I thought it might be interesting to kick off this thread with some data on when the freezing season normally starts in each of the Arctic seas. Here's a graph I made last year (so 2017 is not included in the statistics, but 2017 was a pretty average year):

In a normal year, the Greenland Sea would already have had more than a week of re-freezing, and the CAB and CAA would be about to start.

The graph is based on Piomas volume, so remember that it's a model rather than a measurement. The first day of refreeze is the first day with an increase in volume after the last day at the minimum. The first week represents the start of the first uninterrupted seven-day period of continuous increases in volume after the last day at the minimum.

The graph shows the means, but medians are probably better, so here's a table:

Okhot: first week = 336 (02-Dec) first day = 311 (07-Nov)

Berng: first week = 336 (02-Dec) first day = 312 (08-Nov)

Beauf: first week = 276 (03-Oct) first day = 266 (23-Sep)

Chukc: first week = 289 (16-Oct) first day = 273 (30-Sep)

ESS: first week = 272 (29-Sep) first day = 269 (26-Sep)

Laptv: first week = 277 (04-Oct) first day = 268 (25-Sep)

KaraS: first week = 276 (03-Oct) first day = 265 (22-Sep)

Baren: first week = 297 (24-Oct) first day = 270 (27-Sep)

GrnLS: first week = 249 (06-Sep) first day = 237 (25-Aug)

CAB: first week = 264 (21-Sep) first day = 256 (13-Sep)

CAA: first week = 268 (25-Sep) first day = 258 (15-Sep)

Baffn: first week = 280 (07-Oct) first day = 250 (07-Sep)

Hudsn: first week = 304 (31-Oct) first day = 274 (01-Oct)