Julian - Monday-based week
       December 2017                 January 2018                February 2018       
Mon Tue Wed Thu Fri Sat Sun  Mon Tue Wed Thu Fri Sat Sun  Mon Tue Wed Thu Fri Sat Sun
                335 336 337    1   2   3   4   5   6   7               32  33  34  35
338 339 340 341 342 343 344    8   9  10  11  12  13  14   36  37  38  39  40  41  42
345 346 347 348 349 350 351   15  16  17  18  19  20  21   43  44  45  46  47  48  49
352 353 354 355 356 357 358   22  23  24  25  26  27  28   50  51  52  53  54  55  56
359 360 361 362 363 364 365   29  30  31                   57  58  59