Abstract. Analyses of 32 yr (1979–2010) of Arctic sea ice extents and areas derived from satellite passive microwave radiometers are presented for the Northern Hemisphere as a whole and for nine Arctic regions. There is an overall negative yearly trend of −51.5 ± 4.1 × 10³ km² yr⁻¹ (−4.1 ± 0.3% decade⁻¹) in sea ice extent for the hemisphere. The yearly sea ice extent trends for the individual Arctic regions are all negative except for the Bering Sea: −3.9 ± 1.1 × 10³ km² yr⁻¹ (−8.7 ± 2.5% decade⁻¹) for the Seas of Okhotsk and Japan, +0.3 ± 0.8 × 10³ km² yr⁻¹ (+1.2 ± 2.7% decade⁻¹) for the Bering Sea, −4.4 ± 0.7 × 10³ km² yr⁻¹ (−5.1 ± 0.9% decade⁻¹) for Hudson Bay, −7.6 ± 1.6 × 10³ km² yr⁻¹ (−8.5 ± 1.8% decade⁻¹) for Baffin Bay/Labrador Sea, −0.5 ± 0.3 × 10³ km² yr⁻¹ (−5.9 ± 3.5% decade⁻¹) for the Gulf of St. Lawrence, −6.5 ± 1.1 × 10³ km² yr⁻¹ (−8.6 ± 1.5% decade⁻¹) for the Greenland Sea, −13.5 ± 2.3 × 10³ km² yr⁻¹ (−9.2 ± 1.6% decade⁻¹) for the Kara and Barents Seas, −14.6 ± 2.3 × 10³ km² yr⁻¹ (−2.1 ± 0.3% decade⁻¹) for the Arctic Ocean, and −0.9 ± 0.4 × 10³ km² yr⁻¹ (−1.3 ± 0.5% decade⁻¹) for the Canadian Archipelago. Similarly, the yearly trends for sea ice areas are all negative except for the Bering Sea. On a seasonal basis for both sea ice extents and areas, the largest negative trend is observed for summer with the next largest negative trend being for autumn. Both the sea ice extent and area trends vary widely by month depending on region and season. For the Northern Hemisphere as a whole, all 12 months show negative sea ice extent trends with a minimum magnitude in May and a maximum magnitude in September, whereas the corresponding sea ice area trends are smaller in magnitude and reach minimum and maximum values in March and September.