No primary source (although these exist obviously), but the Royal Netherlands Meteorological Institute has a summary: https://www.knmi.nl/kennis-en-datacentru

No primary source (although these exist obviously), but the Royal Netherlands Meteorological Institute has a summary: https://www.knmi.nl/kennis-en-datacentrum/uitleg/ijsdikte-en-schaatsijs https://www.knmi.nl/kennis-en-datacentrum/uitleg/ijsdikte-en...