The Southern Hemisphere (SH) radiocarbon calibration curve, SHCal13, has been updated to extend measurements to 2145 cal BP and includes new data sets, such as the ANSTO Younger Dryas Huon pine data. The curve is based on IntCal13 data outside the measured range, with an interhemispheric offset of 43 ± 23 years modeled to represent short-term correlations. The offset varies periodically, with an average of about 40 years, due to differences in sea-air CO₂ flux between hemispheres. SHCal13 incorporates data from various sources, including New Zealand, Chile, South Africa, and Tasmania, and extends the calibration curve to 50,000 cal BP using IntCal13 data adjusted by the modeled offset. The new data sets include measurements from Tasmanian Huon pine, New Zealand kauri, and Tasmanian Huon pine, with revised error estimates. The interhemispheric offset is estimated from the difference between the SH curve and IntCal13 at 5-yearly grid points, resulting in an average offset of 43 years with a standard deviation of 23 years. The calibration curve is constructed using a Bayesian approach, with a Markov chain Monte Carlo (MCMC) implementation of the random walk model. The SHCal13 curve is validated by comparing it with IntCal13 data and includes a floating chronology from the Younger Dryas period. The curve is extended to 50,000 cal BP, assuming similar interhemispheric offset levels as measured in the past 2000 years. The study highlights the importance of accurate calibration for radiocarbon dating in the Southern Hemisphere and the need for further research to improve the understanding of interhemispheric 14C offsets. The SHCal13 curve is recommended for use in radiocarbon dating, with the interhemispheric offset adjusted to ensure accurate calibration. The calibration curve is available online and includes data sets from various institutions, such as the Australian Nuclear Science and Technology Organisation, the University of Waikato, and the Center for Accelerator Mass Spectrometry. The study emphasizes the importance of continued research to refine the calibration curve and improve the accuracy of radiocarbon dating in the Southern Hemisphere.The Southern Hemisphere (SH) radiocarbon calibration curve, SHCal13, has been updated to extend measurements to 2145 cal BP and includes new data sets, such as the ANSTO Younger Dryas Huon pine data. The curve is based on IntCal13 data outside the measured range, with an interhemispheric offset of 43 ± 23 years modeled to represent short-term correlations. The offset varies periodically, with an average of about 40 years, due to differences in sea-air CO₂ flux between hemispheres. SHCal13 incorporates data from various sources, including New Zealand, Chile, South Africa, and Tasmania, and extends the calibration curve to 50,000 cal BP using IntCal13 data adjusted by the modeled offset. The new data sets include measurements from Tasmanian Huon pine, New Zealand kauri, and Tasmanian Huon pine, with revised error estimates. The interhemispheric offset is estimated from the difference between the SH curve and IntCal13 at 5-yearly grid points, resulting in an average offset of 43 years with a standard deviation of 23 years. The calibration curve is constructed using a Bayesian approach, with a Markov chain Monte Carlo (MCMC) implementation of the random walk model. The SHCal13 curve is validated by comparing it with IntCal13 data and includes a floating chronology from the Younger Dryas period. The curve is extended to 50,000 cal BP, assuming similar interhemispheric offset levels as measured in the past 2000 years. The study highlights the importance of accurate calibration for radiocarbon dating in the Southern Hemisphere and the need for further research to improve the understanding of interhemispheric 14C offsets. The SHCal13 curve is recommended for use in radiocarbon dating, with the interhemispheric offset adjusted to ensure accurate calibration. The calibration curve is available online and includes data sets from various institutions, such as the Australian Nuclear Science and Technology Organisation, the University of Waikato, and the Center for Accelerator Mass Spectrometry. The study emphasizes the importance of continued research to refine the calibration curve and improve the accuracy of radiocarbon dating in the Southern Hemisphere.