NOAA National Centers for Environmental Information (data by the Rutgers University Global Snow Lab)

Northern Hemisphere snow cover extent climate data record

Weekly maps of snow cover over Northern Hemisphere land from the week of 4 October 1966, on an 88 x 88 polar stereographic grid whose cells cover 10,677 to 41,805 km2: one flag per cell and week (snow covered or not), with each cell's area and a land mask. Snow cover extent in km2 is not in the file; it is the summed area of land cells flagged as snow covered, computed by our transform. Before June 1999 the maps were drawn weekly by NOAA analysts from satellite imagery; since then they come from the US National Ice Center's Interactive Multisensor Snow and Ice Mapping System (IMS), processed at Rutgers. The early years are less reliable. The Rutgers Global Snow Lab's own monthly tables are not used because they carry no licence.

Free to reuse with creditactiveUS federal programmeFetched automatically

Numbers published from it

Northern Hemisphere snow cover extent by month

Licence and credit

Licence: No restrictions on access or use (NOAA CDR Program Open Data Policy)
What the terms say: “In line with these policies, the CDR data sets are non-proprietary, publicly available, and no restrictions are placed upon their use.”
From the producer's terms, checked 2026-10-04; re-checked automatically every week.
Credit we give: Robinson, Estilow and NOAA CDR Program (2012), NOAA Climate Data Record of Northern Hemisphere Snow Cover Extent, Version 1 (v01r01), NOAA National Centers for Environmental Information, doi:10.7289/V5N014G9, accessed {date_accessed}. This CDR was originally developed by David Robinson and colleagues for NOAA's CDR Program.
Copy of the raw file: Allowed: we keep a public copy of every version we use.
Cite as: Robinson, David A.; Estilow, Thomas W.; and NOAA CDR Program (2012): NOAA Climate Data Record (CDR) of Northern Hemisphere (NH) Snow Cover Extent (SCE), Version 1. Weekly snow cover grids, nhsce_v01r01 NetCDF. NOAA National Centers for Environmental Information. doi:10.7289/V5N014G9 {date_accessed}.

Files

NetCDF (CF-1.7): snow_cover_extent(time, y, x) flags 0 = no snow, 1 = snow covered; land (land mask) and area (km2) per cell; time in days since 1966-10-03, one map per week. NCEI replaces the file under a new name at each update; found through discover (the release covering weeks to 31 August 2026 on 2026-10-04).
Downloaded by hand (no stable direct link).

Status

Programme: NCEI updates the file about monthly (the 4 September 2026 release runs to the week of 31 August 2026) and removes the previous one; the fetch finds the new name from the directory listing. The record depends on the US National Ice Center's IMS charts and NOAA's CDR Program; the FY2027 US budget request (April 2026) proposes cutting NCEI by $17.8 million.
Updates: About monthly (weekly maps; each release replaces the file under a new name)
Last check: Unchanged since the last fetch (2026-10-05T11:04:38Z)