Arctic Open-Water Window

Not for navigation. Use at your own risk. Provided as is, without warranty of any kind. This is a historical climate indicator. It does not show current ice conditions in a channel and must not be used for route planning or navigation safety. Use national ice service charts for operations.

Not in this download, free through the API: full-size radar images of the 15 gates, 2015 to 2026, for the weeks that have a usable one. Get a free key at https://heimdallresearch.com/go/signup

What the data shows

• Vilkitsky Strait: 6 open days a year then, 83 now
  At Vilkitsky Strait, mean open days at the 15 percent ice cutoff rose from 5.8 days a year in 1979-1988 to 82.6 days in 2016-2025 (difference +76.8 days).
• Vilkitsky Strait stayed shut in 8 early years. It opened every year from 2016 through 2025.
  Vilkitsky Strait had 8 seasons with zero open days in 1979-1988 and 0 such seasons in 2016-2025.
• Bering Strait is open 53 more days a year than it was
  At Bering Strait, mean open days at the 15 percent cutoff rose from 143.2 days a year in 1979-1988 to 196.5 days in 2016-2025 (difference +53.3 days).
• A typical year at Bering Strait has 173 open days
  Over 45 full seasons (1979 to 2025), Bering Strait had a median of 173 open days at the 15 percent cutoff (range 118 to 234).
• Barrow Strait, Canada: 11 open days a year in 1979-1988, 51 in 2016-2025.
  At Barrow Strait, mean open days at the 15 percent cutoff rose from 11.1 days a year in 1979-1988 to 51.3 days in 2016-2025 (difference +40.2 days).

The numbers, limits, and pandas checks are in README.md in this upload.