Northern Hemisphere Winter Months: Correction on October–March Claim

When Is Winter in the Northern Hemisphere?

The premise is incorrect: Northern latitudes do not experience winter from October to March.

Astronomical vs. Meteorological Winter

Why Not October–March?

• October–November: Autumn (fall). Temperatures cooling but not winter; harvest season; deciduous foliage
• December–February: Core winter months; coldest temperatures; shortest days; snow season
• March: Transition; astronomical winter ends ~March 20; meteorological spring begins March 1

Latitudinal Variation

Winter's severity and duration increase with latitude:

• Mid-latitudes (40°–50°N): ~3–4 months of winter conditions (e.g., New York, London, Beijing)
• High latitudes (50°–66.5°N): ~5–7 months (e.g., Oslo, Stockholm, Anchorage)
• Arctic (>66.5°N): ~8–9 months; polar night; permanent snow/ice cover

But nowhere in the Northern Hemisphere does winter begin in October by any standard definition.

Southern Hemisphere Contrast

In the Southern Hemisphere, winter is June–August (astronomical: ~June 21–Sept 21). The October–March period there covers spring and summer.

The October–March span might describe heating season in some mid-latitude regions or academic/financial periods, but it is not winter.