Update: Tatyana Bezzubkina of the Drobitsky Yar memorial office sent two clarifications, which I thought important to share:
- Babii Yar saw the first attempt to exterminate Jews on a mass scale within a short period of time. The 33 thousand mentioned in the original post were shot within only two days. Overall, however, the victims of Babii Yar number around 100 000.
- Executions in Drobitsky Yar lasted from the end of December 1941 to mid-January 1942. As for temperatures, witness reports start at -15 °C and go all the way down to -25 °C. This may be a matter of time of day.