BIPM Circular T is a monthly publication of the Time Department, source of traceability to Coordinated Universal Time (UTC) for the local realizations UTC(k ) maintained by national institutes. Circular T provides the values of the differences [UTC – UTC (k )] every five days, for about 80 institutes regularly contributing clock and clock comparison data to the BIPM. It includes also other information relevant to the computation of these values.
no. 435 - March 2024 no. 434 - February 2024 no. 433 - January 2024 no. 432 - December 2023 no. 431 - November 2023 no. 430 - October 2023 no. 429 - September 2023 no. 428 - August 2023 no. 427 - July 2023 no. 426 - June 2023 no. 425 - May 2023 no. 424 - April 2023 no. 423 - March 2023 no. 422 - February 2023 no. 421 - January 2023 no. 420 - December 2022 no. 419 - November 2022 no. 418 - October 2022 no. 417 - September 2022 no. 416 - August 2022 no. 415 - July 2022 no. 414 - June 2022 no. 413 - May 2022 no. 412 - April 2022 no. 411 - March 2022 no. 410 - February 2022 no. 409 - January 2022 no. 408 - December 2021 no. 407 - November 2021 no. 406 - October 2021 no. 405 - September 2021 no. 404 - August 2021 no. 403 - July 2021 no. 402 - June 2021 no. 401 - May 2021 no. 400 - April 2021 no. 399 - March 2021 no. 398 - February 2021 no. 397 - January 2021 no. 396 - December 2020 no. 395 - November 2020 no. 394 - October 2020 no. 393 - September 2020 no. 392 - August 2020 no. 391 - July 2020 no. 390 - June 2020 no. 389 - May 2020 no. 388 - April 2020 no. 387 - March 2020 no. 386 - February 2020 no. 385 - January 2020 no. 384 - December 2019 no. 383 - November 2019 no. 382 - October 2019 no. 381 - September 2019 no. 380 - August 2019 no. 379 - July 2019 no. 378 - June 2019 no. 377 - May 2019 no. 376 - April 2019 no. 375 - March 2019 no. 374 - February 2019 no. 373 - January 2019 no. 372 - December 2018 no. 371 - November 2018 no. 370 - October 2018 no. 369 - September 2018 no. 368 - August 2018 no. 367 - July 2018 no. 366 - June 2018 no. 365 - May 2018 no. 364 - April 2018 no. 363 - March 2018 no. 362 - February 2018 no. 361 - January 2018 no. 360 - December 2017 no. 359 - November 2017 no. 358 - October 3017 no. 357 - September 2017 no. 356 - August 2017 no. 355 - July 2017 no. 354 - June 2017 no. 353 - May 2017 no. 352 - April 2017 no. 351 - March 2017 no. 350 - February 2017 no. 349 - January 2017 no. 348 - December 2016 no. 347 - November 2016 no. 346 - October 2016 no. 345 - September 2016 no. 344 - August 2016 no. 343 - July 2016 no. 342 - June 2016 no. 341 - May 2016 no. 340 - April 2016 no. 339 - March 2016 no. 338 - February 2016 no. 337 - January 2016 no. 336 - December 2015 no. 335 - November 2015 no. 334 - October 2015 no. 333 - September 2015 no. 332 - August 2015 no. 331 - July 2014 no. 330 - June 2015 no. 329 - May 2015 no. 328 - April 2015 no. 327 - March 2015 no. 326 - February 2015 no. 325 - January 2015 no. 324 - December 2014 no. 323 - November 2014 no. 322 - October 2014 no. 321 - September 2014 no. 320 - August 2014 no. 319 - July 2014 no. 318 - June 2014 no. 317 - May 2014 no. 316 - April 2014 no. 315 - March 2014 no. 314 - February 2014 no. 313 - January 2014 no. 312 - December 2013 no. 311 - November 2013 no. 310 - October 2013 no. 309 - September 2013 no. 308 - August 2013 no. 307 - July 2013 no. 306 - June 2013 no. 305 - May 2013 no. 304 - April 2013 no. 303 - March 2013 no. 302 - February 2013 no. 301 - January 2013 no. 300 - December 2012 no. 299 - November 2012 no. 298 - October 2012 no. 297 - September 2012 no. 296 - August 2012 no. 295 - July 2012 no. 294 - June 2012 no. 293 - May 2012 no. 292 - April 2012 no. 291 - March 2012 no. 290 - February 2012 no. 289 - January 2012 no. 288 - December 2011 no. 287 - November 2011 no. 286 - October 2011 no. 285 - September 2011 no. 284 - August 2011 no. 283 - July 2011 no. 282 - June 2011 no. 281 - May 2011 no. 280 - April 2011 no. 279 - March 2011 no. 278 - February 2011 no. 277 - January 2011 no. 276 - December 2010 no. 275 - November 2010 no. 274 - October 2010 no. 273 - September 2010 no. 272 - August 2010 no. 271 - July 2010 no. 270 - June 2010 no. 269 - May 2010 no. 268 - April 2010 no. 267 - March 2010 no. 266 - February 2010 no. 265 - January 2010 no. 264 - December 2009 no. 263 - November 2009 no. 262 - October 2009 no. 261 - September 2009 no. 260 - August 2009 no. 259 - July 2009 no. 258 - June 2009 no. 257 - May 2009 no. 256 - April 2009 no. 255 - March 2009 no. 254 - February 2009 no. 253 - January 2009 no. 252 - December 2008 no. 251 - November 2008 no. 250 - October 2008 no. 249 - September 2008 no. 248 - August 2008 no. 247 - July 2008 no. 246 - June 2008 no. 245 - May 2008 no. 244 - April 2008 no. 243 - March 2008 no. 242 - February 2008 no. 241 - January 2008 no. 240 - December 2007 no. 239 - November 2007 no. 238 - October 2007 no. 237 - September 2007 no. 236 - August 2007 no. 235 - July 2007 no. 234 - June 2007 no. 233 - May 2007 no. 232 - April 2007 no. 231 - March 2007 no. 230 - February 2007 no. 229 - January 2007 no. 228 - December 2006 no. 227 - November 2006 no. 226 - October 2006 no. 225 - September 2006 no. 224 - August 2006 no. 223 - July 2006 no. 222 - June 2006 no. 221 - May 2006 no. 220 - April 2006 no. 219 - March 2006 no. 218 - February 2006 no. 217 - January 2006 no. 216 - December 2005 no. 215 - November 2005 no. 214 - October 2005 no. 213 - September 2005 no. 212 - August 2005 no. 211 - July 2005 no. 210 - June 2005 no. 209 - May 2005 no. 208 - April 2005 no. 207 - March 2005 no. 206 - February 2005 no. 205 - January 2005 no. 204 - December 2004 no. 203 - November 2004 no. 202 - October 2004 no. 201 - September 2004 no. 200 - August 2004 no. 199 - July 2004 no. 198 - June 2004 no. 197 - May 2004 no. 196 - April 2004 no. 195 - March 2004 no. 194 - February 2004 no. 193 - January 2004 no. 192 - December 2003 no. 191 - November 2003 no. 190 - October 2003 no. 189 - September 2003 no. 188 - August 2003 no. 187 - July 2003 no. 186 - June 2003 no. 185 - May 2003 no. 184 - April 2003 no. 183 - March 2003 no. 182 - February 2003 no. 181 - January 2003 no. 180 - December 2002 no. 179 - November 2002 no. 178 - October 2002 no. 177 - September 2002 no. 176 - August 2002 no. 175 - July 2002 no. 174 - June 2002 no. 173 - May 2002 no. 172 - April 2002 no. 171 - March 2002 no. 170 - February 2002 no. 169 - January 2002 no. 168 - December 2001 no. 167 - November 2001 no. 166 - October 2001 no. 165 - September 2001 no. 164 - August 2001 no. 163 - July 2001 no. 162 - June 2001 no. 161 - May 2001 no. 160 - April 2001 no. 159 - March 2001 no. 158 - February 2001 no. 157 - January 2001 no. 156 - December 2000 no. 155 - November 2000 no. 154 - October 2000 no. 153 - September 2000 no. 152 - August 2000 no. 151 - July 2000 no. 150 - June 2000 no. 149 - May 2000 no. 148 - April 2000 no. 147 - March 2000 no. 146 - February 2000 no. 145 - January 2000 no. 144 - December 1999 no. 143 - November 1999 no. 142 - October 1999 no. 141 - September 1999 no. 140 - August 1999 no. 139 - July 1999 no. 138 - June 1999 no. 137 - May 1999 no. 136 - April 1999 no. 135 - March 1999 no. 134 - February 1999 no. 133 - January 1999 no. 132 - December 1998 no. 131 - November 1998 no. 130 - October 1998 no. 129 - September 1998 no. 128 - August 1998 no. 127 - July 1998 no. 126 - June 1998 no. 125 - May 1998 no. 124 - April 1998 no. 123 - March 1998 no. 122 - February 1998 no. 121 - January 1998 no. 120 - December 1997 no. 119 - November 1997 no. 118 - October 1997 no. 117 - September 1997 no. 116 - August 1997 no. 115 - July 1997 no. 114 - June 1997 no. 113 - May 1997 no. 112 - April 1997 no. 111 - March 1997 no. 110 - February 1997 no. 109 - January 1997 no. 108 - December 1996 no. 107 - November 1996 no. 106 - October 1996 no. 105 - September 1996 no. 104 - August 1996 no. 103 - July 1996 no. 102 - June 1996 no. 101 - May 1996 no. 100 - April 1996 View
no. 435 - March 2024 no. 434 - February 2024 no. 433 - January 2024 no. 432 - December 2023 no. 431 - November 2023 no. 430 - October 2023 no. 429 - September 2023 no. 428 - August 2023 no. 427 - July 2023 no. 426 - June 2023 no. 425 - May 2023 no. 424 - April 2023 no. 423 - March 2023 no. 422 - February 2023 no. 421 - January 2023 no. 420 - December 2022 no. 419 - November 2022 no. 418 - October 2022 no. 417 - September 2022 no. 416 - August 2022 no. 415 - July 2022 no. 414 - June 2022 no. 413 - May 2022 no. 412 - April 2022 no. 411 - March 2022 no. 410 - February 2022 no. 409 - January 2022 no. 408 - December 2021 no. 407 - November 2021 no. 406 - October 2021 no. 405 - September 2021 no. 404 - August 2021 no. 403 - July 2021 no. 402 - June 2021 no. 401 - May 2021 no. 400 - April 2021 no. 399 - March 2021 no. 398 - February 2021 no. 397 - January 2021 no. 396 - December 2020 no. 395 - November 2020 no. 394 - October 2020 no. 393 - September 2020 no. 392 - August 2020 no. 391 - July 2020 no. 390 - June 2020 no. 389 - May 2020 no. 388 - April 2020 no. 387 - March 2020 no. 386 - February 2020 no. 385 - January 2020 no. 384 - December 2019 no. 383 - November 2019 no. 382 - October 2019 no. 381 - September 2019 no. 380 - August 2019 no. 379 - July 2019 no. 378 - June 2019 no. 377 - May 2019 no. 376 - April 2019 no. 375 - March 2019 no. 374 - February 2019 no. 373 - January 2019 no. 372 - December 2018 no. 371 - November 2018 no. 370 - October 2018 no. 369 - September 2018 no. 368 - August 2018 no. 367 - July 2018 no. 366 - June 2018 no. 365 - May 2018 no. 364 - April 2018 no. 363 - March 2018 no. 362 - February 2018 no. 361 - January 2018 no. 360 - December 2017 no. 359 - November 2017 no. 358 - October 3017 no. 357 - September 2017 no. 356 - August 2017 no. 355 - July 2017 no. 354 - June 2017 no. 353 - May 2017 no. 352 - April 2017 no. 351 - March 2017 no. 350 - February 2017 no. 349 - January 2017 no. 348 - December 2016 no. 347 - November 2016 no. 346 - October 2016 no. 345 - September 2016 no. 344 - August 2016 no. 343 - July 2016 no. 342 - June 2016 no. 341 - May 2016 no. 340 - April 2016 no. 339 - March 2016 no. 338 - February 2016 no. 337 - January 2016 View
no. 001 - January 1988 no. 002 - February 1988 no. 003 - March 1988 no. 004 - April 1988 no. 005 - May 1988 no. 006 - June 1988 no. 007 - July 1988 no. 008 - August 1988 no. 009 - September 1988 no. 010 - October 1988 no. 011 - November 1988 no. 012 - December 1988 no. 013 - January 1989 no. 014 - February 1989 no. 015 - March 1989 no. 016 - April 1989 no. 017 - May 1989 no. 018 - June 1989 no. 019 - July 1989 no. 020 - August 1989 no. 021 - September 1989 no. 022 - October 1989 no. 023 - November 1989 no. 024 - December 1989 no. 025 - January 1990 no. 026 - February 1990 no. 027 - March 1990 no. 028 - April 1990 no. 029 - May 1990 no. 030 - June 1990 no. 031 - July 1990 no. 032 - August 1990 no. 033 - September 1990 no. 034 - October 1990 no. 035 - November 1990 no. 036 - December 1990 no. 037 - January 1991 no. 038 - February 1991 no. 039 - March 1991 no. 040 - April 1991 no. 041 - May 1991 no. 042 - June 1991 no. 043 - July 1991 no. 044 - August 1991 no. 045 - September 1991 no. 046 - October 1991 no. 047 - November 1991 no. 048 - December 1991 no. 049 - January 1992 no. 050 - February 1992 no. 051 - March 1992 no. 052 - April 1992 no. 053 - May 1992 no. 054 - June 1992 no. 055 - July 1992 no. 056 - August 1992 no. 057 - September 1992 no. 058 - October 1992 no. 059 - November 1992 no. 060 - December 1992 no. 061 - January 1993 no. 062 - February 1993 no. 063 - March 1993 no. 064 - April 1993 no. 065 - May 1993 no. 066 - June 1993 no. 067 - July 1993 no. 068 - August 1993 no. 069 - September 1993 no. 070 - October 1993 no. 071 - November 1993 no. 072 - December 1993 no. 073 - January 1994 no. 074 - February 1994 no. 075 - March 1994 no. 076 - April 1994 no. 077 - May 1994 no. 078 - June 1994 no. 079 - July 1994 no. 080 - August 1994 no. 081 - September 1994 no. 082 - October 1994 no. 083 - November 1994 no. 084 - December 1994 no. 085 - January 1995 no. 086 - February 1995 no. 087 - March 1995 no. 088 - April 1995 no. 089 - March 1995 no. 090 - June 1995 no. 091 - July 1995 no. 092 - August 1995 no. 093 - September 1995 no. 094 - October 1995 no. 095 - November 1995 no. 096 - December 1995 no. 097 - January 1996 no. 098 - February 1996 no. 099 - March 1996 no. 100 - April 1996 no. 101 - May 1996 no. 102 - June 1996 no. 103 - July 1996 no. 104 - August 1996 no. 105 - September 1996 no. 106 - October 1996 no. 107 - November 1996 no. 108 - December 1996 no. 109 - January 1997 no. 110 - February 1997 no. 111 - March 1997 no. 112 - April 1997 no. 113 - May 1997 no. 114 - June 1997 no. 115 - July 1997 no. 116 - August 1997 no. 117 - September 1997 no. 118 - October 1997 no. 119 - November 1997 no. 120 - December 1997 no. 121 - January 1998 no. 122 - February 1998 no. 123 - March 1998 no. 124 - April 1998 View
BIPM Circular T has been published without interruption since 1 March 1988. The quality of the results has increased progressively following the progress made in clocks and time and frequency transfer techniques, in parallel with the constant improvement in the treatment of the data at the BIPM. The contents and presentation of Circular T have also evolved; from January 2016 an interactive HTML version gives access to complete information about the local time scales and the time links used for clock comparison.