Year B2000 NOAA CDR B & R Mar/Apr (pre-satellite) Mar/Apr (satellite) Mar/Apr (13-year mean) Lower diff Mar/Apr (lower bound) Upper dif Mar/Apr (upper bound) conf int Lower limit AVG Upper limit Jun sat Jun (satellite) Jun (linear trend) Mar/Apr (linear trend)
1922 33.76 33.76 -1.91 -4.2681 0.4401 2.3541 31.41 33.76 36.12
1923 38.49 38.49 2.81 0.4163 5.2123 2.398 36.09 38.49 40.89
1924 37.5 37.5 1.82 -0.4837 4.1252 2.3044 35.19 37.5 39.8
1925 34.01 34.01 -1.67 -3.999 0.6648 2.3319 31.68 34.01 36.34
1926 37.97 37.97 2.3 -0.1178 4.7131 2.4155 35.56 37.97 40.39
1927 36.78 36.78 1.1 -1.2164 3.4177 2.317 34.46 36.78 39.09
1928 40.06 40.06 4.38 1.2712 1.8923 -1.0894 6.8722 3.6318 2.49 37.57 40.06 42.55
1929 38.71 38.71 3.04 1.4761 0.6262 -0.8796 5.4474 3.8317 2.4106 36.3 38.71 41.12
1930 35.67 35.67 0.0 1.3574 -2.3103 -0.9921 2.3075 3.707 2.3089 33.37 35.67 37.98
1931 37.65 37.65 1.98 1.2214 -0.3859 -1.1269 4.3379 3.5696 2.3619 35.29 37.65 40.01
1932 36.58 36.58 0.91 1.2188 -1.396 -1.1275 3.2072 3.565 2.3016 34.28 36.58 38.88
1933 36.11 36.11 0.44 1.1126 -1.8772 -1.2239 2.7488 3.4492 2.313 33.8 36.11 38.42
1934 37.01 37.01 1.34 1.1458 -1.0424 -1.1892 3.7187 3.4808 2.3805 34.63 37.01 39.39
1935 36.43 36.43 0.75 0.9616 -1.5414 -1.3656 3.04 3.2888 2.2907 34.13 36.43 38.72
1936 36.95 36.95 1.27 0.8901 -1.0458 -1.4341 3.5901 3.2143 2.3179 34.63 36.95 39.27
1937 35.73 35.73 0.05 0.8665 -2.2356 -1.4573 2.34 3.1903 2.2878 33.44 35.73 38.02
1938 33.98 33.98 -1.7 0.6871 -4.007 -1.6324 0.605 3.0067 2.306 31.67 33.98 36.28
1939 36.59 36.59 0.92 0.6818 -1.3716 -1.6401 3.2072 3.0036 2.2894 34.3 36.59 38.88
1940 37.21 37.21 1.53 0.6642 -0.7656 -1.6587 3.8289 2.987 2.2972 34.91 37.21 39.5
1941 37.66 37.66 1.99 0.5223 -0.4001 -1.795 4.3758 2.8397 2.3879 35.28 37.66 40.05
1942 37.78 37.78 2.11 0.6342 -0.2639 -1.6855 4.479 2.9538 2.3714 35.41 37.78 40.16
1943 35.37 35.37 -0.31 0.6328 -2.6128 -1.6857 1.995 2.9512 2.3039 33.06 35.37 37.67
1944 35.32 35.32 -0.36 0.6713 -2.6624 -1.6481 1.9518 2.9908 2.3071 33.01 35.32 37.63
1945 36.51 36.51 0.84 0.7456 -1.4954 -1.5809 3.1672 3.0722 2.3313 34.18 36.51 38.84
1946 35.88 35.88 0.21 0.9617 -2.1189 -1.3729 2.5327 3.2962 2.3258 33.56 35.88 38.21
1947 35.17 35.17 -0.51 0.8131 -2.8147 -1.5212 1.8033 3.1474 2.309 32.86 35.17 37.48
1948 37.88 37.88 2.2 0.878 -0.1177 -1.4523 4.5237 3.2083 2.3207 35.56 37.88 40.2
1949 36.93 36.93 1.25 0.8862 -1.048 -1.44 3.5557 3.2123 2.3018 34.63 36.93 39.23
1950 36.23 36.23 0.55 1.225 -1.7479 -1.1066 2.8551 3.5566 2.3015 33.93 36.23 38.53
1951 34.94 34.94 -0.73 1.423 -3.1326 -0.9116 1.6629 3.7576 2.3978 32.54 34.94 37.34
1952 39.4 39.4 3.73 1.4683 1.3325 -0.8666 6.1193 3.8033 2.3934 37.01 39.4 41.8
1953 35.28 35.28 -0.4 1.5878 -2.6942 -0.7457 1.8941 3.9213 2.2942 32.98 35.28 37.57
1954 38.51 38.51 2.83 1.8953 0.4966 -0.4418 5.1687 4.2325 2.336 36.17 38.51 40.84
1955 37.89 37.89 2.21 1.5949 -0.104 -0.7423 4.5301 3.9322 2.317 35.57 37.89 40.21
1956 39.77 39.77 4.1 1.4295 1.7214 -0.91 6.4707 3.769 2.3747 37.4 39.77 42.15
1957 37.89 37.89 2.22 1.4905 -0.1283 -0.8502 4.5657 3.8312 2.347 35.55 37.89 40.24
1958 37.1 37.1 1.43 1.8234 -0.9105 -0.5165 3.7613 4.1633 2.3359 34.77 37.1 39.44
1959 37.44 37.44 1.76 1.7015 -0.5468 -0.6319 4.0658 4.0348 2.3063 35.13 37.44 39.74
1960 39.17 39.17 3.49 1.6878 1.1355 -0.6463 5.8498 4.022 2.3572 36.81 39.17 41.53
1961 33.97 33.97 -1.7 1.6433 -4.0241 -0.6353 0.6188 3.9218 2.3215 31.65 33.97 36.29
1962 34.78 34.78 -0.9 1.2461 -3.2274 -1.0207 1.4345 3.5129 2.331 32.45 34.78 37.11
1963 37.02 37.02 1.35 0.9576 -0.9708 -1.309 3.6638 3.2241 2.3173 34.71 37.02 39.34
1964 39.27 39.27 3.59 0.9467 1.2061 -1.2517 5.9803 3.1452 2.3871 36.88 39.27 41.66
1965 37.82 37.82 2.14 0.9767 -0.1683 -1.1386 4.449 3.0919 2.3086 35.51 37.82 40.13
1966 35.1 35.1 -0.58 0.8723 -2.8818 -1.175 1.7271 2.9196 2.3044 32.79 35.1 37.4
1967 35.64 37.93 37.93 2.2534 0.6097 0.64 -1.3511 3.8669 2.5706 1.6134 36.32 37.93 39.54 14.37 3.7507 2.0325 0.9639
1968 34.51 32.73 32.73 -2.9496 0.6951 -5.1135 -1.1907 -0.7856 2.5809 2.164 30.56 32.73 34.89 7.95 -2.6643 1.91 0.9156
1969 39.77 36.02 36.02 0.3449 0.8157 -2.0267 -0.9744 2.7166 2.6058 2.3716 33.65 36.02 38.39 1.7875 0.8673
1970 37.32 37.75 37.75 2.0775 0.7082 0.6158 -1.0396 3.5391 2.456 1.4617 36.29 37.75 39.22 12.51 1.8942 1.665 0.819
1971 38.14 37.49 37.49 1.8144 0.4091 0.5603 -1.236 3.0686 2.0542 1.2542 36.24 37.49 38.74 9.98 -0.6419 1.5425 0.7707
1972 37.3 36.08 36.08 0.4029 0.3349 -1.0196 -1.2398 1.8255 1.9097 1.4225 34.66 36.08 37.5 11.17 0.5576 1.42 0.7224
1973 33.97 35.76 35.76 0.0794 0.6356 -1.1546 -0.864 1.3135 2.1352 1.234 34.52 35.76 36.99 12.11 1.4883 1.2975 0.6741
1974 35.89 35.08 35.08 -0.5931 0.6414 -1.9393 -0.879 0.7532 2.1618 1.3462 33.74 35.08 36.43 11.64 1.0201 1.175 0.6258
1975 35.58 36.35 36.35 0.6714 1.0474 -0.4147 -0.479 1.7576 2.5737 1.0862 35.26 36.35 37.43 11.08 0.4618 1.0525 0.5775
1976 36.97 35.63 35.63 -0.0511 1.0521 -1.8186 -0.3828 1.7165 2.487 1.7675 33.86 35.63 37.39 13.89 3.2765 0.93 0.5292
1977 33.96 35.38 35.38 -0.2946 0.8513 -1.3465 -0.563 0.7574 2.2657 1.0519 34.33 35.38 36.43 11.76 1.1428 0.8075 0.4809
1978 36.23 36.85 36.85 1.1755 0.7156 -0.2186 -0.6761 2.5695 2.1074 1.394 35.46 36.85 38.25 14.97 4.3544 0.685 0.4326
1979 38.8 39.01 39.01 3.3315 0.8874 2.004 -0.4715 4.6589 2.2463 1.3274 37.68 39.01 40.33 12.15 1.5348 0.5625 0.3843
1980 37.03 38.01 38.01 2.329 0.8309 0.445 -0.5133 4.2129 2.1751 1.8839 36.12 38.01 39.89 10.9 0.2831 0.44 0.336
1981 33.83 38.0 38.0 2.3279 0.992 0.0862 -0.3356 4.5697 2.3196 2.2417 35.76 38.0 40.25 13.42 2.8028 0.3175 0.2877
1982 37.17 36.08 36.08 0.4065 0.8367 -0.7756 -0.527 1.5885 2.2003 1.182 34.9 36.08 37.26 9.08 -1.5372 0.195 0.2394
1983 33.64 35.14 35.14 -0.5326 0.7263 -1.7271 -0.589 0.662 2.0417 1.1946 33.95 35.14 36.34 10.35 -0.2649 0.0725 0.1911
1984 36.56 35.73 35.73 0.0504 0.507 -0.9103 -0.7985 1.0112 1.8125 0.9608 34.77 35.73 36.69 8.45 -2.1651 -0.05 0.1428
1985 37.83 38.31 38.31 2.6359 0.2798 1.6406 -0.9957 3.6313 1.5554 0.9953 37.32 38.31 39.31 13.41 2.7927 -0.1725 0.0945
1986 35.65 35.02 35.02 -0.6556 -0.1386 -1.6987 -1.4213 0.3876 1.1441 1.0431 33.98 35.02 36.06 11.03 0.4127 -0.295 0.0462
1987 37.64 37.18 37.18 1.5019 -0.45 0.3718 -1.6971 2.6321 0.7972 1.1301 36.05 37.18 38.31 12.16 1.5381 -0.4175 -0.0021
1988 34.77 34.33 34.33 -1.3481 -0.7224 -2.9031 -1.9234 0.207 0.4787 1.5551 32.77 34.33 35.88 8.06 -2.5593 -0.54 -0.0504
1989 35.05 34.19 34.19 -1.4856 -0.7687 -2.6252 -2.0157 -0.3459 0.4782 1.1396 33.05 34.19 35.33 9.19 -1.4313 -0.6625 -0.0987
1990 31.75 32.53 32.53 -3.1456 -0.6004 -4.0696 -1.8814 -2.2215 0.6806 0.924 31.61 32.53 33.45 7.17 -3.4466 -0.785 -0.147
1991 34.0 33.9 33.9 -1.7781 -0.666 -2.7826 -1.9898 -0.7735 0.6578 1.0046 32.89 33.9 34.9 10.64 0.0231 -0.9075 -0.1953
1992 33.57 33.57 -2.1081 -0.8429 -3.528 -2.232 -0.6881 0.5463 1.4199 32.15 33.57 34.99 10.26 -0.3561 -1.03 -0.2436
1993 33.96 33.96 -1.7191 -0.8788 -3.1413 -2.2609 -0.2968 0.5033 1.4222 32.53 33.96 35.38 7.91 -2.704 -1.1525 -0.2919
1994 34.46 34.46 -1.2131 -1.1231 -2.8551 -2.5494 0.429 0.3032 1.642 32.82 34.46 36.11 9.0 -1.6203 -1.275 -0.3402
1995 35.48 35.48 -0.1966 -1.0962 -1.9753 -2.5 1.5822 0.3076 1.7787 33.7 35.48 37.26 9.48 -1.1358 -1.3975 -0.3885
1996 37.33 37.33 1.656 -1.1274 0.0185 -2.5254 3.2934 0.2706 1.6374 35.69 37.33 38.97 11.25 0.6376 -1.52 -0.4368
1997 34.87 34.87 -0.8026 -0.8505 -2.3194 -2.2757 0.7143 0.5748 1.5168 33.36 34.87 36.39 10.11 -0.5108 -1.6425 -0.4851
1998 36.01 36.01 0.3369 -0.8706 -1.5087 -2.314 2.1826 0.5728 1.8457 34.17 36.01 37.86 9.48 -1.136 -1.765 -0.5334
1999 34.55 34.55 -1.1231 -0.767 -2.0744 -2.1973 -0.1717 0.6633 0.9513 33.6 34.55 35.5 8.7 -1.919 -1.8875 -0.5817
2000 34.0 34.0 -1.6736 -0.6742 -3.378 -2.0923 0.0309 0.744 1.7045 32.3 34.0 35.71 9.72 -0.8982 -2.01 -0.63
2001 34.68 34.68 -0.9981 -0.7378 -2.2607 -2.1267 0.2646 0.651 1.2626 33.42 34.68 35.94 8.75 -1.8709 -2.1325 -0.6783
2002 33.78 33.78 -1.8921 -0.915 -2.956 -2.2711 -0.8281 0.441 1.064 32.72 33.78 34.85 9.23 -1.3922 -2.255 -0.7266
2003 36.13 36.13 0.455 -1.1523 -0.8237 -2.4787 1.7337 0.1742 1.2787 34.85 36.13 37.41 10.25 -0.367 -2.3775 -0.7749
2004 33.64 33.64 -2.0399 -1.1852 -3.2801 -2.4947 -0.7997 0.1242 1.2402 32.4 33.64 34.88 9.76 -0.8618 -2.5 -0.8232
2005 34.92 34.92 -0.7609 -1.1978 -2.0107 -2.464 0.4888 0.0685 1.2497 33.67 34.92 36.16 9.07 -1.5517 -2.6225 -0.8715
2006 35.16 35.16 -0.5125 -1.218 -1.7766 -2.5088 0.7516 0.0728 1.2641 33.9 35.16 36.43 8.41 -2.2111 -2.745 -0.9198
2007 33.64 33.64 -2.0406 -0.9772 -3.3015 -2.1368 -0.7796 0.1825 1.261 32.37 33.64 34.9 8.38 -2.2398 -2.8675 -0.9681
2008 33.18 33.18 -2.5 -0.915 -3.8527 -2.2711 -1.1473 0.441 1.3527 31.82 33.18 34.53 6.69 -3.9292 -2.99 -1.0164
2009 34.25 34.25 -1.4285 -1.1523 -2.6807 -2.4787 -0.1762 0.1742 1.2522 33.0 34.25 35.5 7.13 -3.4912 -3.1125 -1.0647
2010 34.45 34.45 -1.231 -1.1852 -2.5266 -2.4947 0.0646 0.1242 1.2956 33.15 34.45 35.74 6.02 -4.5986 -3.235 -1.113
2011 35.85 35.85 0.1741 -1.1978 -1.1107 -2.464 1.4588 0.0685 1.2847 34.57 35.85 37.13 6.05 -4.5719 -3.3575 -1.1613
2012 34.29 34.29 -1.3861 -1.218 -2.6557 -2.5088 -0.1164 0.0728 1.2697 33.02 34.29 35.56 4.92 -5.6956 -3.48 -1.2096
2013 37.13 1.4574 -0.9772 1.4574 -2.1368 1.4574 0.1825 35.86 37.13 38.4 6.01 -4.6035 -3.6025 -1.2579