The timing of sea ice advance and retreat has implications for marine travel in coastal Arctic communities and industry as well as ecosystem needs like marine organism migration. Although sea ice extent and timing varies greatly from year to year, recent studies have found an overall shortening of the sea ice season since 1980. Because the economy and environment rely on the freeze-up and break-up of sea ice, the ability to reliably predict these processes on a local scale is important. A new study, supported by the Climate Program Office’s Climate Observations and Monitoring (COM) Program, uses satellite measurements of sea ice going back to 1978 to develop indicators of advance and retreat in ten coastal locations distributed around the Arctic. A group of researchers from the University of Alaska, Fairbanks, including COM-funded scientist John Walsh, found that ice tethered along shorelines is relatively stable, with an earlier freeze-up date and later break-up date compared to offshore ice. But even so, the results, published in The Cryosphere, show that rising global temperatures have driven shorter sea ice seasons in all ten study sites. This trend is amplified by the ocean’s ability to absorb and retain more solar heat during the newly extended time period with exposed, open ocean. This study offers an Arctic perspective to a COM effort to use long-term climate observations to advance global climate indicators that will bolster our understanding of Earth’s systems in a changing climate.