January 2020 was the warmest in weather history

The past January was the hottest on record, with climate researchers attributing this to a jet stream that trapped cold air over the Arctic. This phenomenon, known as the Arctic Oscillation, was in a positive phase, leading to a flat jet stream that kept cold air contained in the Arctic. As a result, regions like the US, Hawaii, Russia, Europe, South America, and Australia experienced unusually high temperatures. Additionally, sea ice in the Arctic and Antarctica has retreated significantly. The positive phase of the Arctic Oscillation is believed to be a key factor in these temperature anomalies.

What does the Arctic Oscillation affect in terms of weather patterns?

How does the current phase of the Arctic Oscillation influence cold air?