January — the first month of the year

Name and historical background

The month takes its name from Janus, the two-faced Roman god of doorways and beginnings. The assignment of January as the start of the year evolved with Roman calendar reforms and later with medieval and early modern calendar practice. The month appears in both the Julian calendar and the widely used Gregorian calendar, which corrected accumulated drift in the former system.

Calendar characteristics and weekday patterns

January always has 31 days (31 days) and directly follows December, while preceding February. In common years January begins on the same weekday as October, and in leap years it shares a starting weekday with April and July. It ends on the same weekday as February and October in non-leap years, and with July in leap years. These relationships are useful for planning recurring events and constructing perpetual calendars.

Seasonal placement and cultural observances

In the Northern Hemisphere January is a mid-winter month, often linked to cold weather, shorter daylight, and post-holiday recovery. In the Southern Hemisphere it is a mid-summer month with warm temperatures and different seasonal activities. Many public holidays and observances occur during January: globally recognized New Year's Day, religious feasts such as Epiphany in some traditions, and national commemorations in various countries. Some observances follow a fixed date while others are movable, for example those set to a particular weekday.

Uses, examples and significance

Organizations and individuals commonly use January as a fiscal or planning boundary: budgets, academic terms, and resolutions frequently begin at the start of the month. Astronomically, the month includes part of the Sun's transit through the constellations associated with Capricorn and Aquarius in tropical zodiac systems. Meteorologists often treat January as the coldest month in many northern regions and the hottest in parts of the south.

Notable facts and links

• January is often used to mark the start of annual statistics and legal periods in many jurisdictions; see general references to the concept of a year.
• The month's place in different calendar systems can affect historical date interpretation; compare practices in different month definitions and how they were applied in common years versus leap years.
• Understanding weekday alignments with months such as April, July, and October helps when creating repeating schedules.
• For cultural observances and calendars in practice, consult country-specific guides and official sources as implementations vary (February and other months often have related lists).