MISSOULA — While Astronomical Winter (what our calendars say) doesn't happen until December 21st this year, Meteorological Winter begins today, December 1st.
Meteorological seasons begin at the beginning of the month in three-month increments: Fall is September-November; Winter is December-February; Spring is March-May, and Summer is June-August.
These seasons are defined by the annual temperature cycle, rather than Earth's position relative to the sun, in order to facilitate consistent record-keeping for weather and climate statistics.
It's way easier than starting halfway through a month!
So, while we still have 20 days until the Winter Solstice, it's sure is feeling like Winter with our incoming system!
Of note: The Climate Prediction Center says a weak La Niña (typically wetter/colder than average for the PACNW) is favored to continue into the early Northern Hemisphere winter, with a transition to ENSO-neutral conditions most likely in January-March 2026 (61% chance).
