A large, rapid multi-method attribution study, supported by observational and large ensemble model analyses, indicates with high confidence that extremely warm periods such as the 6 months of January – June 2020 over the Siberian region would have been at least 2 °C cooler in a world without human influence. Similar events have a best estimate return time in the current climate of around 130 years and are now more than 600 times as likely to occur as they would have been at the beginning of the 20th century; with the best estimate orders of magnitude larger. By 2050 we expect such a regional warm period in the first 6 months of the year to be at least another 0.5 °C warmer, and possibly up to 5 °C warmer, with similar 6-month regional temperatures becoming correspondingly more frequent. Statements regarding the very high June daily maximum temperatures (38 °C) such as were reported at Verkhoyansk can be made only with much lower confidence. Nevertheless, results also indicate a large increase in the likelihood of such temperatures and, with more confidence, an increase in extreme daily maxima of more than 1 °C when comparing the climate of 1900 to the present day.