Clean_Air 06Z temperature 1986 - -36.8 -52.8 -55.4 -63.0 -63.4 -60.0 -59.9 - - -39.4 -29.5 1987 -27.7 -41.7 -52.2 -59.5 -60.0 -58.5 - - - - -41.9 -29.4 1988 -28.0 -43.3 -49.3 -60.0 -62.4 -58.9 -63.5 -58.2 -58.3 -50.6 -39.4 -30.2 1989 -31.3 -41.7 -55.1 -61.8 -63.0 -63.4 -59.4 -57.5 -59.8 -53.3 -38.7 -26.8 1990 -28.5 -42.0 -56.7 -61.4 -63.2 -58.3 -59.3 -63.0 - - - -25.7 1991 -28.7 -38.6 -57.4 -59.8 -61.6 -61.0 -58.0 -61.5 -53.7 -52.7 -39.7 -26.7 1992 -29.2 -43.7 -58.2 -55.3 -60.2 -56.8 -61.9 -62.8 -60.0 -48.1 -39.6 -30.1 1993 -29.6 -43.7 -55.0 -60.2 -59.7 -62.7 -60.0 -66.7 -61.8 - - - 1994 - -43.7 -54.1 -57.7 -58.7 -55.6 -63.5 -59.6 -58.4 -50.6 -36.9 -27.9 1995 -29.9 -40.6 -53.8 -59.6 -60.0 -59.9 -56.5 -62.3 -65.5 -48.2 -37.7 -26.3 1996 -28.0 -37.1 -56.5 -55.5 -61.6 -60.1 -56.4 -53.9 -60.3 -52.2 -35.1 -25.3 1997 -27.7 -42.8 -55.5 -57.1 -59.1 -58.8 -66.3 -60.7 -60.8 -52.8 -33.9 -26.1 1998 -26.2 -37.8 -53.2 -63.2 -59.2 -56.2 -60.5 -64.1 -64.0 -54.1 -36.7 -26.5 1999 -24.9 -40.3 -54.9 -61.5 -58.2 -58.8 -63.9 -57.6 -63.2 -50.1 -37.7 -29.8 2000 -28.8 -42.0 -55.6 -62.2 -60.6 -60.0 -61.2 -59.5 -61.2 -50.4 -33.3 -26.3 2001 -28.0 -38.4 -55.1 -60.4 -59.0 -58.8 -61.6 -64.8 -57.1 -52.7 -34.4 -25.8 2002 -25.4 -40.6 -51.0 -53.7 -57.1 -62.7 -54.4 -58.3 -57.9 -48.6 -38.5 -29.3 2003 -26.2 -36.9 -52.2 -55.8 -57.7 -62.6 -62.3 -54.2 -60.0 -48.5 -34.4 -22.0 2004 -24.2 -35.6 -52.9 -53.2 -56.7 -60.4 -66.0 -60.0 -52.8 -46.9 -35.9 -22.0 2005 - - - - - - - - - - - - 2006 - - - - - - - - - - - - 2007 - - - - - - - - - - - - 2008 - - - - - - - - - - - - 2009 - - - - - - - - - - - - 2010 - - - - - - - - - - - - 2011 - - - - - - - - - - - - 2012 - - - - - - - - - - - - 2013 - - - - - - - - - - - - 2014 - - - - - - - - - - - - 2015 - - - - - - - - - - - - 2016 - - - - - - - - - - - - 2017 - - - - - - - - - - - - 2018 - - - - - - - - - - - - 2019 - - - - - - - - - - - - 2020 - - - - - - - - - - - - 2021 - - - - - - - - - - - - 2022 - - - - - - - - - - - - 2023 - - - - - - - - - - - - 2024 - - - - - - - - - - - -