Mean Rate of Change ( °C / Century )

Since: 1760 1810 1860 1910 1960 1990
Iowa 0.49
± 0.26
0.85
± 0.29
1.12
± 0.19
0.81
± 0.11
2.39
± 0.15
4.18
± 0.60
Contiguous United States - 0.66
± 0.25
0.76
± 0.18
0.87
± 0.08
2.16
± 0.16
2.76
± 0.36
United States - 0.69
± 0.24
0.80
± 0.16
0.89
± 0.08
2.36
± 0.13
2.42
± 0.39
North America - 0.82
± 0.23
1.02
± 0.18
1.11
± 0.11
2.90
± 0.19
4.72
± 0.28
Northern Hemisphere - 0.79
± 0.16
0.96
± 0.10
1.19
± 0.05
2.56
± 0.20
3.56
± 0.20
Global Land 0.43
± 0.18
0.79
± 0.13
0.91
± 0.08
1.11
± 0.03
2.16
± 0.11
2.78
± 0.13

Regional Climate Variability

Difference from Global Land Average ( °C, 95% range )

Smoothing Monthly Annual Five-year Ten-year Twenty-year
± 3.62 ± 1.32 ± 0.60 ± 0.42 ± 0.34

Correlation to Global Land Average (R value)

Smoothing Monthly Annual Five-year Ten-year Twenty-year
0.47 0.66 0.85 0.91 0.92

Variability in Monthly Means ( °C, 95% range )

Jan Feb Mar Apr May Jun
± 5.55 ± 5.37 ± 4.71 ± 3.43 ± 3.23 ± 2.70
Jul Aug Sep Oct Nov Dec
± 2.59 ± 2.46 ± 2.70 ± 3.46 ± 3.81 ± 5.09

History of Temperature Stations

Evolution of Climate Extremes

Mean of Daily High Temperature

Mean of Daily Low Temperature