October 2, 2025: The Arctic sea ice has experienced a larger increase rate for this week of 8.96% (last week’s increase rate was 2.68%), from the level on 09/25/2025 of 4.817 M km2 to 5.291 M km2 for this week.  The sea ice extent for 2025 to date has now risen one more spot to 9th place for the lowest sea ice extent for this day of the year as noted below when the lowest sea ice extent was at 4.138 M km2 on 10/02/2012. Ranking of lowest sea ice extent for the day of the post, values in M km2 : 2012 4.1382020 4.4792007 4.6582024 4.7632023 4.8572019 4.8812018 5.0382011 5.1802025 5.291 The negative sea ice anomaly this week was less than the anomaly of -0.91083 M km2 on 09/25/2025 to a lower negative anomaly of -0.88801  M km2 on 10/02/2025, and so more anomalously negative for this time of year.  

September 25, 2025: The Arctic sea ice has experienced a larger increase rate for this week of 2.68% (last week’s increase rate was 0.36%), from the level on 09/18/2025 of 4.688 M km2 to 4.817 M km2 for this week. So, we are now definitely in the sea ice increase season. The sea ice extent for 2025 to date has now risen by two spots to 10th place for the lowest sea ice extent for this day of the year as noted below when the lowest sea ice extent was at 3.735 M km2 on 09/25/2012.  Ranking of lowest sea ice extent for the day of the post, values in M km2 : 2012    3.7352020    4.2122007    4.2132023    4.4362019    4.4702024    4.5032008    4.7292011    4.7482018    4.7702025    4.817 The negative sea ice anomaly this week was greater than the anomaly of -0.78362 M km2 on 09/18/2025 to a higher negative anomaly of -0.91083  M km2 on 09/25/2025, and so more anomalously negative for this time of year.

September 18, 2025: Arctic sea ice has experienced another very small increase rate for this week of 0.36% (last week’s increase rate was 0.09%), from the level on 09/11/2025 of 4.671 M km2 to 4.688 M km2 for this week.  So, it looks like we have probably reached that transition point to the sea ice increase season. The sea ice extent for 2025 to date has now dropped one more spot to 12th place for the lowest sea ice extent for this day of the year as noted below when the lowest sea ice extent was at 3.452 M km2 on 09/18/2012.  Ranking of lowest sea ice extent for the day of the post, values in M km2 : 2012    3.4522020    3.9042007    4.1562019    4.1662023    4.2672024    4.3262016    4.4412008    4.5482011    4.5762015    4.5852010    4.6282025    4.688 The negative sea ice anomaly this week was greater than the anomaly of -0.74646 M km2 on 09/11/2025 to a higher negative anomaly of -0.78362  M km2 on 09/18/2025, and so more anomalously negative for this time of year.

September 11, 2025: (Eight days since the last post) the Arctic sea ice has experienced a very small increase rate for this week of 0.09% (last week’s decrease rate was 2.95%), from the level on 09/03/2025 of 4.667 M km2 to 4.671 M km2 for this week.  The sea ice extent for 2025 to date has now dropped one spot to 11th place for the lowest sea ice extent for this day of the year as noted below when the lowest sea ice extent was at 3.416 M km2 on 09/11/2012.  So, it looks like we are right on the precipice of the change in sea ice seasonality from the decrease season to the increase season; next week’s data should help us with that.  Since last week, sea ice has been oscillating between loss and gain a total of four times, but the last three days have all been trending up. Ranking of lowest sea ice extent for the day of the post, values in M km2 : 2012    3.4162020    3.8492007    4.2152016    4.2382024    4.2502023    4.2582019    4.3192011    4.3462015    4.4712008    4.5772025    4.671 The negative sea ice anomaly this week was lower than the anomaly of -0.90148 M km2 on 09/03/2025 to a lesser negative anomaly of -0.74646  M ...

September 3, 2025: (Only six days since the last post) the Arctic sea ice has experienced a lesser decrease rate for this week of 2.95% (last week’s decrease rate was 5.48%), from the level on 08/28/2025 of 4.809 M km2 to 4.667 M km2 for this week.  The sea ice extent for 2025 to date remains in 10th place for the lowest sea ice extent for this day of the year as noted below when the lowest sea ice extent was at 3.562 M km2 on 09/03/2012. 2012    3.5622020    4.0412024    4.2902016    4.3102019    4.3592007    4.4502023    4.4982015    4.5092011    4.5272025    4.667 The negative sea ice anomaly this week was lower than the anomaly of -0.98266 M km2 on 08/28/2025 to a lesser negative anomaly of -0.90148  M km2 on 09/03/2025, and so less anomalously negative for this time of year.

Arctic sea ice has experienced a lesser decrease rate for this week of 5.48% (last week’s decrease rate was 6.37%), from the level on 08/21/2025 of 5.088 M km2 to 4.809 M km2 for this week.  The sea ice extent for 2025 to date has now slipped two more places to 10th place for the lowest sea ice extent for this day of the year as noted below when the lowest sea ice extent was at 3.758 M km2 on 08/28/2012: 2012    3.7582020    4.3542024    4.4052016    4.6202019    4.6322023    4.6782015    4.6932007    4.7182011    4.7992025    4.809 The negative sea ice anomaly this week was lower than the anomaly of -1.0879 M km2 on 08/21/2025 to a lesser negative anomaly of -0.98266  M km2 on 08/28/2025, and so less anomalously negative for this time of year.