Johan Castberg lies in the Barents Sea at 72.45° N, 20.15° E. Significant wave height there exceeds 2 m about 53% of the time across the whole year, roughly 16 days a month on average. The roughest month is January, with a mean significant wave height of 3.3 m and seas above 2 m about 82% of the time; the calmest is July, with a mean of 1.4 m and about 14% of the time above 2 m. Waves above 4 m occur about 11% of the time.
Open this location in the explorer
Mean significant wave height and the percentage of time the significant wave height is above each level, by calendar month. The last row combines the months weighted by their length in days.
| Month | Mean Hs (m) | % above 1 m | % above 1.5 m | % above 2 m | % above 2.5 m | % above 3 m | % above 4 m |
|---|---|---|---|---|---|---|---|
| January | 3.3 | 100% | 95% | 82% | 66% | 50% | 25% |
| February | 3.2 | 100% | 95% | 82% | 65% | 48% | 24% |
| March | 2.9 | 98% | 91% | 75% | 56% | 39% | 18% |
| April | 2.3 | 94% | 78% | 57% | 37% | 22% | 6.2% |
| May | 1.8 | 84% | 57% | 34% | 19% | 9.6% | 2.3% |
| June | 1.5 | 76% | 42% | 20% | 9.6% | 4.1% | 0.7% |
| July | 1.4 | 71% | 34% | 14% | 5.5% | 1.9% | 0.3% |
| August | 1.5 | 75% | 38% | 17% | 8.1% | 3.8% | 0.7% |
| September | 2.0 | 91% | 68% | 44% | 25% | 14% | 3.8% |
| October | 2.6 | 98% | 87% | 67% | 45% | 29% | 10% |
| November | 2.7 | 99% | 89% | 69% | 49% | 34% | 14% |
| December | 3.1 | 99% | 93% | 79% | 61% | 44% | 21% |
| Year | 2.4 | 90% | 72% | 53% | 37% | 25% | 11% |
Wind at 10 m across the year: typically 8.1 m/s (16 kn), top 10% above 13.5 m/s (26 kn). Monthly means run from 6.2 m/s in July to 9.8 m/s in January.
Weather windows: a typical month fits about 12 separate 24 h periods with significant wave height below 2 m, fewest in January (about 3.3). Periods do not overlap, so a 30 day month holds at most 30.
Nearest mapped asset to the data point: JOHAN CASTBERG CD, platform, about 345 m water depth, 2 km away. Source: Norwegian Offshore Directorate FactPages (Norwegian Licence for Open Government Data).
Data basis: WAVERYS wave reanalysis (Copernicus Marine) + ERA5 wind, 1980-2023, 3 hourly. Data point 72.40° N, 20.20° E (0.2° grid), 6 km from the named position, 128,568 samples. Values are for the nearest grid cell and are not interpolated.
Generated using E.U. Copernicus Marine Service Information: WAVERYS global wave reanalysis [1980-2023], 3 hourly significant wave height, peak period and direction. Wind statistics from the ERA5 reanalysis (Copernicus C3S) on its 0.5 degree grid (wind, direction rose, diurnal cycle and ENSO split 1980-2024). Neither the European Commission nor ECMWF nor Mercator Ocean is responsible for any use of this information.
How the numbers are made: How it works. Other locations: all location pages.
Thrust Maritime, Sea State Explorer, Johan Castberg, WAVERYS wave reanalysis (Copernicus Marine) + ERA5 wind 1980-2023, 3 hourly, page built 2026-10-23, accessed [date], https://seastate.thrustm.com/locations/johan-castberg.html
Weather windows decide when a lift can go. Thrust Maritime provides specialist lifting solutions for subsea operations.