Calendar

Yearly calendar with all months at a glance - holidays and moon phases

January

February

March

April

May

June

July

August

September

October

November

December

2025 Holidays at a Glance

Common year - 365 days

•📅 Friday the 13th Frequency: Every calendar year has at least one Friday the 13th, and at most three - the longest possible gap between Friday the 13ths is 14 months (426 days), and any month starting on a Sunday will have a Friday the 13th.
•🗓️ The Calendar Repeat Cycle: There are only 14 possible calendar configurations (7 for common years starting on each day of the week, 7 for leap years) - meaning every year is identical to some past year, and 2026's calendar is exactly the same as 1999, 2010, and will repeat in 2037.
•⏰ The Lost 11 Days: When Britain switched from the Julian to Gregorian calendar in September 1752, they skipped 11 days - going directly from September 2 to September 14 - causing riots from people who believed their lives were being "shortened."
•🌍 New Year's Not Universal: While most of the world celebrates January 1, the Chinese New Year (Jan 21-Feb 20), Islamic New Year (moves 11 days earlier each year), Jewish New Year (Rosh Hashanah, Sept/Oct), and Ethiopian New Year (Sept 11) all fall on completely different dates.
•📊 October/December Name Paradox: October means "8th month" and December means "10th month" in Latin, but they're the 10th and 12th months - this happened because the Roman calendar originally started in March, making October the 8th and December the 10th until January and February were added later.

•🕐 Daylight Saving Time Origins: DST was first seriously proposed by Benjamin Franklin in 1784 as a joke in an essay titled "An Economical Project" - Germany was first to actually implement it in 1916 during WWI to conserve fuel.
•⏰ The Longest Day: The day DST begins has only 23 hours (spring forward) - the day it ends has 25 hours (fall back) - babies born during the "fall back" hour can have ambiguous birth times.
•🌍 Samoa's Lost Day: In 2011, Samoa skipped December 30 entirely (going from Dec 29 to Dec 31) to switch from UTC-11 to UTC+13 - they crossed the International Date Line to align with trading partners.
•📅 The Longest Month: October 1582 in Catholic countries had only 21 days - 10 days (Oct 5-14) were skipped to realign the calendar with solar years when adopting the Gregorian system.
•🗓️ Soviet Revolutionary Calendar: The USSR experimented with a 5-day week (1929-1931) and 6-day week (1931-1940) to maximize factory productivity - workers had different days off, preventing family time together.
•⏰ Y2K Was Overblown (Kind Of): The Year 2000 problem cost $300-600 billion to fix worldwide, but only because of massive preparation - unremediated systems did fail (nuclear plant monitors, slot machines, credit cards).
•📅 Year 2038 Problem: On January 19, 2038 at 3:14:07 AM UTC, 32-bit Unix timestamps will overflow - systems still using 32-bit time (IoT devices, embedded systems) will reset to December 13, 1901.