Transition | Northeast | Northwest | Year to date IPS | Characteristics of the years |
1999, 2003 | 1988 |
| >2 | Extreme humidity |
1988; 1995; 2004; 2007; 2008 | 1989; 1991; 1995; 2008; 2014 | 1991; 1998; 2003; 2009; 2012 | [1; 2] | Very rainy |
1984; 1985; 1987; 1989; 2006; 2010; 2014 | 1984; 1994; 1996; 1998; 2004; 2009; 2010; 2012 | 1986; 1994; 1995; 1996; 2004; 2007; 2008; 2010; 2011 | [0.25; 1] | Moderately rainy |
1994, 1996; 1997; 2002 | 1985; 1993; 1999; 2000; 2003; 2007; | 1981; 1982; 1999; 2005 | [−0.25; 0.25] | Normal |
1981; 1986; 1990; 1991; 1992; 1993; 2000; 2001; 2009; 2011; 2012; 2013 | 1981; 1982; 1986 1990; 1992; 1997; 2002; 2006; 2011; 2016 | 1984; 1987; 1988; 1989; 1990; 1992; 1993; 1997; 2001; 2002; 2006; 2015; 2016 | [−1; −0.25] | Moderately dry |
1982; 1998; 2005; 2015; 2016 | 1987; 2001; 2005; 2013; 2015 | 1985; 2000; 2013; 2014 | IPS [−2; −1] | Very dry |
1983 | 1983 | 1983 | IPS < −2 | Extreme drought |