Roaring Forties Index

Data is from ERSSTv4.

Year January February March April May June July August September October November December
1870 0.069 0.049 0.033 0.040 -0.009 0.022 0.002 0.110 0.025 0.073 0.051 0.113
1871 0.029 0.039 -0.017 -0.070 0.011 0.032 -0.148 -0.140 -0.095 0.003 0.141 0.103
1872 0.129 0.059 0.123 0.170 0.211 0.122 0.192 0.270 0.135 0.153 0.251 0.243
1873 0.109 0.169 -0.047 -0.220 -0.249 0.022 0.242 0.250 0.195 0.133 0.091 -0.077
1874 -0.141 -0.021 -0.167 -0.230 -0.129 -0.018 0.132 0.160 0.105 0.173 0.111 0.213
1875 0.079 0.049 0.083 0.230 0.181 0.122 -0.018 -0.020 -0.025 0.013 -0.029 -0.027
1876 0.189 0.199 0.093 0.020 -0.199 -0.188 -0.118 0.030 0.065 0.073 0.041 0.043
1877 -0.041 0.039 -0.167 -0.210 -0.109 -0.128 -0.078 -0.040 0.005 -0.007 0.021 -0.007
1878 -0.171 -0.171 -0.137 -0.170 -0.329 -0.298 -0.118 -0.120 -0.085 0.023 -0.029 -0.117
1879 -0.071 0.249 0.283 0.210 0.201 0.212 0.242 0.240 0.295 0.333 0.261 0.273
1880 0.229 0.229 0.013 -0.020 -0.039 -0.138 -0.028 -0.010 -0.015 -0.047 -0.079 -0.147
1881 -0.091 0.009 0.123 0.110 0.091 -0.028 -0.068 -0.030 0.125 0.073 0.041 0.103
1882 -0.071 0.239 0.243 0.240 0.071 0.072 0.072 0.240 0.225 0.223 0.091 0.023
1883 -0.051 0.029 -0.017 0.030 0.041 0.082 0.102 0.130 0.045 0.143 0.201 0.113
1884 0.009 0.019 0.163 0.140 0.001 -0.148 -0.248 -0.110 0.025 0.213 0.071 -0.137
1885 -0.281 -0.161 -0.077 0.070 0.031 0.032 0.152 0.180 0.115 -0.097 -0.289 -0.267
1886 -0.311 -0.311 -0.427 -0.410 -0.089 -0.148 -0.038 -0.010 0.045 0.003 0.061 -0.147
1887 -0.131 -0.161 -0.197 -0.060 -0.099 -0.038 -0.198 -0.230 -0.275 -0.227 -0.239 -0.367
1888 -0.431 -0.591 -0.387 -0.320 -0.319 -0.458 -0.368 -0.300 -0.265 -0.097 -0.059 -0.047
1889 -0.131 -0.261 -0.107 -0.060 0.131 -0.028 -0.198 -0.170 -0.195 -0.027 -0.059 -0.107
1890 -0.301 -0.361 -0.297 -0.360 -0.299 -0.338 -0.238 -0.150 -0.185 -0.197 -0.139 -0.257
1891 -0.221 0.069 0.083 -0.150 -0.199 -0.368 -0.218 -0.230 -0.255 -0.257 -0.229 -0.077
1892 -0.211 -0.261 -0.287 -0.360 -0.249 -0.418 -0.228 -0.240 0.035 -0.057 -0.129 -0.087
1893 0.149 0.079 -0.157 -0.290 -0.229 0.122 -0.168 -0.130 -0.095 -0.067 -0.059 -0.177
1894 -0.211 -0.201 -0.177 -0.310 -0.479 -0.338 -0.268 -0.260 -0.145 -0.097 -0.019 -0.007
1895 0.079 -0.021 -0.247 -0.260 -0.299 -0.278 -0.098 -0.080 -0.035 -0.097 -0.029 0.173
1896 0.269 0.109 -0.097 -0.160 -0.169 -0.288 -0.238 -0.230 -0.085 0.013 -0.339 -0.507
1897 -0.561 -0.401 -0.457 -0.410 -0.319 -0.328 -0.228 -0.200 -0.145 -0.137 -0.109 -0.277
1898 -0.241 -0.351 -0.437 -0.360 -0.299 -0.288 -0.158 -0.030 -0.235 -0.307 -0.189 -0.067
1899 -0.161 -0.251 -0.267 -0.300 -0.229 -0.108 -0.098 -0.080 -0.095 -0.197 -0.199 -0.267
1900 0.229 0.229 0.013 -0.020 -0.039 -0.138 -0.028 -0.010 -0.015 -0.047 -0.079 -0.147
1901 -0.361 -0.111 -0.167 -0.180 -0.179 -0.118 -0.248 -0.280 -0.375 -0.397 -0.299 -0.277
1902 -0.121 -0.231 -0.297 -0.310 -0.319 -0.418 -0.518 -0.480 -0.395 -0.427 -0.359 -0.387
1903 -0.401 -0.381 -0.287 -0.100 -0.129 -0.168 -0.158 -0.220 -0.295 -0.197 -0.129 -0.027
1904 -0.171 -0.291 -0.147 -0.330 -0.409 -0.388 -0.438 -0.410 -0.345 -0.237 -0.099 -0.267
1905 -0.301 -0.421 -0.287 -0.320 -0.349 -0.268 -0.368 -0.270 -0.235 -0.167 -0.179 -0.157
1906 -0.211 -0.201 -0.237 0.000 -0.149 -0.198 -0.118 -0.020 -0.125 -0.187 -0.189 -0.187
1907 -0.231 -0.191 -0.097 -0.220 -0.199 -0.168 -0.138 -0.160 -0.155 -0.157 -0.349 -0.357
1908 -0.381 -0.301 -0.337 -0.240 -0.359 -0.298 -0.258 -0.270 -0.285 -0.217 -0.279 -0.387
1909 -0.431 -0.281 -0.227 -0.350 -0.319 -0.388 -0.378 -0.310 -0.315 -0.407 -0.269 -0.367
1910 -0.241 -0.221 -0.187 -0.240 -0.129 -0.068 0.022 -0.190 -0.245 -0.347 -0.499 -0.627
1911 -0.531 -0.611 -0.727 -0.660 -0.649 -0.528 -0.388 -0.350 -0.305 -0.277 -0.279 -0.187
1912 -0.031 -0.051 -0.007 -0.030 -0.149 -0.248 -0.078 -0.090 -0.145 -0.197 -0.159 -0.087
1913 -0.011 -0.271 -0.357 -0.170 -0.339 -0.248 -0.218 -0.280 -0.295 -0.337 -0.229 -0.227
1914 -0.251 -0.281 -0.197 -0.240 -0.139 -0.158 -0.108 -0.040 -0.085 -0.157 -0.069 -0.117
1915 -0.231 -0.061 0.053 0.150 -0.069 -0.208 -0.208 -0.220 -0.055 -0.017 -0.119 -0.427
1916 -0.201 -0.201 -0.027 0.190 0.211 -0.028 -0.098 -0.030 -0.145 -0.287 -0.209 -0.087
1917 -0.021 0.029 0.283 0.270 0.351 0.162 0.072 0.120 0.085 0.203 -0.019 -0.137
1918 -0.111 0.039 0.103 0.040 0.081 -0.048 -0.098 -0.130 -0.215 -0.257 -0.369 -0.277
1919 -0.211 -0.191 -0.107 0.060 0.401 -0.118 -0.048 -0.050 -0.265 -0.387 -0.129 -0.267
1920 -0.421 -0.531 -0.417 -0.340 -0.439 -0.328 -0.358 -0.420 -0.115 -0.067 -0.319 -0.267
1921 -0.191 -0.271 -0.467 -0.790 -0.869 -0.738 -0.308 -0.040 -0.165 -0.137 -0.319 -0.227
1922 -0.211 -0.191 0.013 -0.210 -0.419 -0.398 -0.368 -0.200 -0.115 -0.257 -0.059 0.133
1923 -0.061 -0.281 -0.197 -0.100 -0.209 -0.038 -0.138 -0.410 -0.575 -0.297 0.021 -0.257
1924 -0.251 -0.581 -0.577 -0.480 -0.189 -0.428 -0.468 -0.600 -0.465 -0.677 -0.739 -0.537
1925 -0.361 -0.441 -0.447 -0.580 -0.439 -0.498 -0.588 -0.560 -0.325 -0.397 -0.259 -0.227
1926 -0.241 -0.341 -0.477 -0.510 -0.429 -0.488 -0.218 -0.230 -0.345 -0.447 -0.489 -0.497
1927 -0.531 -0.601 -0.467 -0.320 -0.249 -0.298 -0.018 -0.130 -0.105 -0.517 -0.409 -0.427
1928 -0.561 -0.711 -0.557 -0.430 -0.399 -0.678 -0.408 -0.430 -0.385 -0.467 -0.439 -0.567
1929 -0.511 -0.511 -0.477 -0.440 -0.419 -0.498 -0.238 -0.410 -0.465 -0.457 -0.459 -0.617
1930 -0.691 -0.281 -0.437 -0.400 -0.329 -0.178 -0.318 -0.160 -0.215 -0.067 -0.159 -0.417
1931 -0.561 -0.381 -0.107 -0.300 -0.409 -0.078 0.032 -0.110 -0.335 -0.297 -0.269 -0.327
1932 -0.201 -0.151 -0.187 -0.340 -0.389 -0.478 -0.678 -0.720 -0.715 -0.577 -0.519 -0.387
1933 -0.491 -0.451 -0.477 -0.270 -0.269 -0.348 -0.148 -0.210 -0.325 -0.447 -0.419 -0.347
1934 -0.331 -0.281 -0.187 -0.010 -0.329 -0.328 -0.338 -0.080 -0.055 -0.187 -0.249 -0.377
1935 -0.441 -0.431 -0.467 -0.340 0.001 -0.138 -0.168 -0.150 -0.315 -0.247 -0.219 -0.187
1936 -0.221 -0.281 -0.387 -0.440 -0.259 -0.278 -0.338 -0.300 -0.115 -0.067 -0.019 -0.037
1937 0.019 -0.131 -0.097 -0.090 -0.179 -0.438 -0.338 -0.060 0.005 0.013 0.041 0.063
1938 -0.011 -0.001 -0.037 0.060 -0.039 -0.048 0.082 0.170 0.055 0.153 -0.149 -0.167
1939 -0.241 0.049 0.213 0.090 -0.089 0.022 -0.178 -0.130 -0.045 0.063 0.181 0.043
1940 -0.181 -0.011 -0.047 0.050 -0.139 -0.148 -0.078 -0.250 -0.235 -0.207 -0.199 -0.077
1941 0.129 0.049 0.123 -0.100 -0.639 -0.628 -0.238 0.140 0.095 -0.057 -0.069 0.073
1942 0.039 0.169 0.093 0.240 0.381 0.372 0.072 -0.340 -0.305 -0.097 0.011 0.013
1943 0.129 0.099 -0.067 -0.090 0.101 0.152 0.092 -0.040 0.055 0.193 0.161 0.163
1944 0.179 0.089 0.423 0.450 0.421 0.132 -0.038 -0.110 -0.035 -0.057 0.001 -0.077
1945 0.149 0.119 0.023 0.010 0.101 0.012 0.072 0.040 0.095 0.073 0.181 -0.097
1946 -0.041 -0.171 -0.357 -0.240 -0.319 -0.268 -0.028 0.130 0.065 -0.017 -0.019 -0.067
1947 -0.071 -0.131 -0.117 -0.040 0.061 0.262 0.102 -0.070 -0.155 -0.177 -0.089 -0.137
1948 -0.211 0.049 0.063 -0.160 -0.089 0.062 -0.088 -0.010 -0.075 -0.087 -0.209 -0.187
1949 -0.121 -0.041 0.013 0.020 -0.199 -0.228 0.022 -0.020 -0.035 0.043 -0.089 0.003
1950 -0.001 -0.161 -0.337 -0.270 -0.059 0.112 0.242 -0.050 -0.155 -0.267 -0.159 -0.167
1951 -0.161 -0.211 -0.197 -0.220 -0.389 -0.118 -0.108 -0.080 -0.165 -0.027 -0.009 0.093
1952 0.209 0.259 0.163 -0.150 -0.359 -0.178 0.042 0.270 0.095 0.093 0.041 0.093
1953 -0.051 -0.101 -0.197 -0.010 -0.019 0.182 0.222 0.120 -0.045 -0.197 -0.199 -0.257
1954 -0.331 -0.101 0.033 -0.030 0.111 0.182 0.242 0.130 0.155 0.273 -0.009 -0.037
1955 -0.301 -0.381 -0.207 -0.270 -0.029 0.322 0.142 -0.050 -0.165 -0.077 -0.049 0.033
1956 0.149 0.099 -0.037 -0.080 0.031 0.162 0.052 0.160 -0.165 0.063 0.211 0.053
1957 -0.081 -0.131 0.003 -0.100 0.371 0.282 0.242 -0.070 -0.205 -0.157 -0.129 -0.127
1958 -0.061 -0.091 -0.167 -0.090 -0.049 0.392 0.092 -0.040 0.005 -0.077 -0.059 0.033
1959 -0.171 -0.081 -0.047 -0.090 0.131 0.062 0.072 0.070 -0.135 -0.057 0.001 -0.217
1960 -0.041 -0.101 -0.047 -0.160 0.111 0.232 0.072 0.010 -0.095 0.143 0.091 0.053
1961 0.039 0.049 0.153 0.200 0.021 0.022 -0.238 -0.070 0.065 0.013 -0.009 -0.027
1962 -0.031 -0.051 0.063 0.040 0.081 0.402 -0.058 0.000 0.105 -0.117 -0.099 -0.037
1963 -0.071 -0.041 0.003 0.010 -0.379 -0.018 -0.078 -0.010 -0.045 -0.117 -0.139 -0.077
1964 -0.091 -0.151 -0.087 -0.100 -0.119 -0.118 -0.088 0.250 0.255 0.013 -0.129 -0.077
1965 -0.001 0.059 -0.027 -0.150 -0.259 0.222 0.142 0.210 0.205 0.023 -0.019 -0.027
1966 0.049 -0.141 -0.237 -0.230 -0.059 0.082 -0.018 -0.320 -0.145 -0.197 -0.129 -0.027
1967 -0.061 -0.001 -0.087 0.010 -0.009 0.132 0.002 0.140 0.005 -0.047 -0.069 0.003
1968 0.099 0.099 -0.017 -0.010 0.311 0.222 0.032 -0.140 -0.135 0.183 0.131 0.233
1969 0.289 0.259 0.263 0.320 0.331 0.172 0.112 0.240 0.165 -0.037 -0.009 0.153
1970 0.169 0.089 0.053 0.090 -0.049 -0.028 -0.098 0.050 0.195 0.273 0.191 0.183
1971 0.199 0.089 0.153 0.120 0.061 0.302 0.062 0.200 0.225 0.283 0.261 0.263
1972 0.259 0.289 0.183 0.100 -0.039 -0.118 0.052 0.070 0.145 0.153 0.231 0.163
1973 0.119 0.089 0.083 0.240 0.251 0.032 0.052 0.020 0.035 0.043 0.211 0.063
1974 0.039 -0.041 -0.037 0.050 0.191 0.202 0.122 0.190 -0.135 0.093 0.121 0.153
1975 0.219 0.269 0.253 0.280 0.231 0.062 -0.058 0.120 0.195 0.063 0.111 0.113
1976 0.169 0.189 0.143 0.090 0.091 0.082 0.032 -0.050 0.125 0.343 0.471 0.733
1977 0.729 0.629 0.493 0.440 0.341 0.312 0.432 0.350 0.325 0.363 0.371 0.273
1978 0.189 0.169 0.303 0.340 0.381 0.232 0.272 0.020 0.065 0.223 0.371 0.433
1979 0.479 0.499 0.483 0.470 0.401 0.432 0.442 0.400 0.415 0.483 0.521 0.533
1980 0.589 0.659 0.513 0.390 0.401 0.402 0.352 0.330 0.355 0.423 0.461 0.483
1981 0.229 0.229 0.013 -0.020 -0.039 -0.138 -0.028 -0.010 -0.015 -0.047 -0.079 -0.147
1982 0.359 0.259 0.243 0.310 0.301 0.302 0.212 0.320 0.565 0.503 0.411 0.473
1983 0.549 0.499 0.433 0.330 0.281 0.232 0.242 0.310 0.305 0.253 0.231 0.363
1984 0.409 0.409 0.313 0.280 0.221 0.142 0.152 0.280 0.345 0.273 0.361 0.503
1985 0.559 0.589 0.513 0.470 0.461 0.352 0.372 0.370 0.425 0.443 0.361 0.413
1986 0.379 0.399 0.363 0.350 0.351 0.352 0.402 0.340 0.355 0.393 0.321 0.283
1987 0.389 0.399 0.353 0.320 0.271 0.222 0.262 0.270 0.265 0.243 0.311 0.323
1988 0.319 0.289 0.283 0.330 0.311 0.272 0.202 0.170 0.265 0.273 0.251 0.333
1989 0.369 0.329 0.363 0.350 0.331 0.312 0.232 0.190 0.315 0.363 0.441 0.463
1990 0.559 0.619 0.533 0.490 0.511 0.462 0.442 0.300 0.245 0.343 0.341 0.323
1991 0.379 0.389 0.413 0.430 0.441 0.492 0.562 0.510 0.415 0.403 0.351 0.393
1992 0.469 0.509 0.453 0.470 0.441 0.452 0.342 0.240 0.285 0.403 0.391 0.443
1993 0.429 0.509 0.423 0.430 0.421 0.412 0.442 0.440 0.485 0.433 0.271 0.223
1994 0.289 0.329 0.383 0.390 0.501 0.442 0.422 0.310 0.305 0.223 0.221 0.333
1995 0.289 0.289 0.273 0.270 0.321 0.292 0.222 0.300 0.265 0.243 0.231 0.263
1996 0.299 0.359 0.483 0.480 0.411 0.362 0.322 0.350 0.355 0.413 0.441 0.493
1997 0.509 0.509 0.463 0.540 0.531 0.502 0.462 0.470 0.555 0.493 0.411 0.363
1998 0.429 0.379 0.353 0.470 0.491 0.442 0.482 0.430 0.365 0.323 0.361 0.363
1999 0.369 0.339 0.373 0.330 0.261 0.242 0.202 0.140 0.205 0.273 0.341 0.363
2000 0.589 0.659 0.513 0.390 0.401 0.402 0.352 0.330 0.355 0.423 0.461 0.483
2001 0.319 0.289 0.333 0.370 0.371 0.282 0.242 0.230 0.335 0.413 0.421 0.483
2002 0.509 0.539 0.443 0.450 0.341 0.302 0.382 0.370 0.415 0.323 0.271 0.303
2003 0.329 0.399 0.413 0.400 0.371 0.332 0.302 0.260 0.275 0.273 0.231 0.273
2004 0.349 0.429 0.413 0.370 0.261 0.212 0.182 0.240 0.275 0.293 0.231 0.263
2005 0.279 0.369 0.343 0.310 0.351 0.312 0.292 0.220 0.275 0.313 0.321 0.333
2006 0.339 0.339 0.323 0.380 0.321 0.342 0.362 0.300 0.235 0.183 0.181 0.223
2007 0.239 0.239 0.183 0.200 0.251 0.252 0.212 0.180 0.205 0.203 0.191 0.233
2008 0.209 0.269 0.203 0.250 0.281 0.232 0.242 0.250 0.225 0.213 0.211 0.273
2009 0.289 0.269 0.273 0.300 0.331 0.362 0.372 0.310 0.315 0.303 0.361 0.523
2010 0.499 0.479 0.453 0.390 0.351 0.292 0.302 0.330 0.345 0.333 0.361 0.423
2011 0.489 0.469 0.443 0.420 0.471 0.452 0.482 0.430 0.425 0.413 0.401 0.373
2012 0.419 0.469 0.353 0.340 0.361 0.342 0.402 0.400 0.435 0.423 0.371 0.403
2013 0.439 0.489 0.493 0.550 0.611 0.532 0.462 0.310 0.245 0.373 0.421 0.403
2014 0.319 0.359 0.443 0.590 0.491 0.412 0.362 0.370 0.385 0.353 0.341 0.383
2015 0.359 0.379 0.403 0.390 0.381 0.342 0.362 0.340 0.355 0.383 0.301 0.313
2016 0.449 0.469 0.423 0.430 0.401 0.392 0.432 0.370 0.375 0.443 0.431

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