Observed values of UT1-TAI, 1962-1999
TT-UT1 can be obtained from this table using the expression
TT-UT1 = 32.184s - (UT1-TAI)
The uncertainty of UT1-TAI is smaller than 2 units of the last digit listed.
| DATE | UT1-TAI (s) | DATE | UT1-TAI | DATE | UT1-TAI | DATE | UT1-TAI | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1962 | JAN 1 APR 1 JUL 1 OCT 1 | -1.813 -1.936 -2.058 -2.142 | 1972 | JAN 1 APR 1 JUL 1 OCT 1 | -10.045 -10.347 -10.638 -10.888 | 1982 | JAN 1 APR 1 JUL 1 OCT 1 | -19.983 -20.184 -20.391 -20.550 | 1992 | JAN 1 APR 1 JUL 1 OCT 1 | -26.1252 -26.3562 -26.5569 -26.7146 |
| 1963 | JAN 1 APR 1 JUL 1 OCT 1 | -2.289 -2.407 -2.551 -2.659 | 1973 | JAN 1 APR 1 JUL 1 OCT 1 | -11.189 -11.489 -11.771 -12.016 | 1983 | JAN 1 APR 1 JUL 1 OCT 1 | -20.773 -21.036 -21.250 -21.400 | 1993 | JAN 1 APR 1 JUL 1 OCT 1 | -26.9378 -27.1734 -27.4010 -27.5748 |
| 1964 | JAN 1 APR 1 JUL 1 OCT 1 | -2.847 -3.043 -3.217 -3.350 | 1974 | JAN 1 APR 1 JUL 1 OCT 1 | -12.301 -12.553 -12.814 -13.023 | 1984 | JAN 1 APR 1 JUL 1 OCT 1 | -21.6042 -21.7603 -21.9018 -22.0074 | 1994 | JAN 1 APR 1 JUL 1 OCT 1 | -27.8004 -28.0202 -28.2171 -28.3738 |
| 1965 | JAN 1 APR 1 JUL 1 OCT 1 | -3.558 -3.761 -3.964 -4.139 | 1975 | JAN 1 APR 1 JUL 1 OCT 1 | -13.292 -13.554 -13.799 -13.999 | 1985 | JAN 1 APR 1 JUL 1 OCT 1 | -22.1587 -22.3058 -22.4516 -22.5333 | 1995 | JAN 1 APR 1 JUL 1 OCT 1 | -28.6014 -28.8437 -29.0614 -29.2196 |
| 1966 | JAN 1 APR 1 JUL 1 OCT 1 | -4.360 -4.586 -4.817 -5.006 | 1976 | JAN 1 APR 1 JUL 1 OCT 1 | -14.274 -14.545 -14.812 -15.054 | 1986 | JAN 1 APR 1 JUL 1 OCT 1 | -22.6872 -22.8157 -22.9292 -23.0058 | 1996 | JAN 1 APR 1 JUL 1 OCT 1 | -29.4447 -29.6292 -29.8129 -29.9362 |
| 1967 | JAN 1 APR 1 JUL 1 OCT 1 | -5.248 -5.476 -5.700 -5.871 | 1977 | JAN 1 APR 1 JUL 1 OCT 1 | -15.336 -15.595 -15.850 -16.062 | 1987 | JAN 1 APR 1 JUL 1 OCT 1 | -23.1382 -23.2788 -23.3972 -23.4816 | 1997 | JAN 1 APR 1 JUL 1 OCT 1 | -30.1110 -30.2914 -30.4731 -30.6087 |
| 1968 | JAN 1 APR 1 JUL 1 OCT 1 | -6.111 -6.344 -6.573 -6.775 | 1978 | JAN 1 APR 1 JUL 1 OCT 1 | -16.351 -16.651 -16.917 -17.123 | 1988 | JAN 1 APR 1 JUL 1 OCT 1 | -23.6356 -23.7823 -23.9100 -23.9771 | 1998 | JAN 1 APR 1 JUL 1 OCT 1 | -30.7818 -30.9622 -31.1004 -31.1582 |
| 1969 | JAN 1 APR 1 JUL 1 OCT 1 | -7.021 -7.274 -7.521 -7.734 | 1979 | JAN 1 APR 1 JUL 1 OCT 1 | -17.402 -17.670 -17.918 -18.112 | 1989 | JAN 1 APR 1 JUL 1 OCT 1 | -24.1159 -24.2443 -24.3857 -24.4899 | 1999 | JAN 1 APR 1 JUL 1 | -31.2833 -31.3840 -31.4801 |
| 1970 | JAN 1 APR 1 JUL 1 OCT 1 | -7.997 -8.271 -8.526 -8.722 | 1980 | JAN 1 APR 1 JUL 1 OCT 1 | -18.355 -18.582 -18.792 -18.970 | 1990 | JAN 1 APR 1 JUL 1 OCT 1 | -24.6713 -24.8631 -25.0386 -25.1803 | |||
| 1971 | JAN 1 APR 1 JUL 1 OCT 1 | -8.985 -9.237 -9.503 -9.741 | 1981 | JAN 1 APR 1 JUL 1 OCT 1 | -19.196 -19.414 -19.629 -19.777 | 1991 | JAN 1 APR 1 JUL 1 OCT 1 | -25.3813 -25.5871 -25.7735 -25.9204 | |||