I always dated the beginning of spring, N. Hemisphere, from the exact time of the vernal equinox, which is now on March 20, and some years, including next year, on the 19th. Farmer's Almanac: https://www.farmersalmanac.com/spring-equinox-first-day-spring.
I've seen climatologists or meteorologists define "winter" as Dec 5 - March 5, because ~Jan 20 is the low point for long-term temperature average.
Strictly speaking we are at the end of astronomical winter :)
I always dated the beginning of spring, N. Hemisphere, from the exact time of the vernal equinox, which is now on March 20, and some years, including next year, on the 19th. Farmer's Almanac: https://www.farmersalmanac.com/spring-equinox-first-day-spring.