Simplified ice chart and reference charts
Ice extent
About the charts and the graph
The ice chart of the whole Baltic Sea (pdf) is published in the autumn on Mondays and Thursdays and daily when the amount of ice increases until ice break-up in spring. It represents current ice situation, ice breaker positions and assistance restrictions in the Baltic Sea area.
The simplified chart and reference charts are updated once a week. The first one represents Finnish sea areas simplified ice situation. The reference charts represent the normal ice situation of that time (2008–2022 median), last week´s situation, last year´s situation and the positions of the ice breakers.
Daily ice extent graph on the Baltic Sea (km²). The blue envelope curves show the largest and smallest ice extents (min–max) and fractiles (25 %–75 %) of the ice seasons 2007–2021. The green line (50 %) is the median extent of the seasons 2007–2021. The black dotted line is the previous ice season's (2021–2022) ice extent, and the solid black line is the current ice season's (2022–2023) extent.
Products are generated using EU Copernicus Marine Service Information.
More about the data in the charts and the graph on the page Marine weather online.
Explanation of chart's Finnish words
jäätä: ice
vettä: water
haurasta: rotten ice