October

Key takeaways

October belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect October to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of October from memory before moving on to harder problems.

Reference excerpt

October is the 10th month of the year in the Julian and Gregorian calendars. Its length is 31 days. The eighth month in the old calendar of Romulus c. 750 BC, October retained its name (from Latin and Greek ôctō meaning "eight") after January and February were inserted into the calendar that had originally been created by the Romans. In Ancient Rome, one of three Mundus patet would take place on October 5, Meditrinalia October 11, Augustalia on October 12, October Horse on October 15, and Armilustrium on October 19. These dates do not correspond to the modern Gregorian calendar. Among the Anglo-Saxons, it was known as Winterfylleth (Ƿinterfylleþ), because at this full moon, winter was supposed to begin. October is commonly associated with the season of autumn in parts of the Northern Hemisphere, and spring in parts of the Southern Hemisphere, where it is the seasonal equivalent to April in the Northern Hemisphere and vice versa.

Symbols

October's birthstones are the tourmaline and opal. Its birth flower is the calendula. The zodiac signs are Libra (until October 22) and Scorpio (from October 23 onward).

Observances This list does not necessarily imply either official status or general observance.

Non-Gregorian: 2026 dates (All Baha'i, Islamic, and Jewish observances begin at the sundown prior to the date listed, and end at sundown of the date in question unless otherwise noted.)

List of observances set by the Bahá'í calendar List of observances set by the Chinese calendar List of observances set by the Hebrew calendar List of observances set by the Islamic calendar List of observances set by the Solar Hijri calendar

Month-long Black History Month in the United Kingdom In Catholic Church tradition, October is the Month of the Holy Rosary. Breast Cancer Awareness Month Health Literacy Month International Walk to School Month Medical Ultrasound Awareness Month Rett Syndrome Awareness Month World Blindness Awareness Month World Menopause Month Vegetarian Awareness Month

United States The last two to three weeks in October (and, occasionally, the first week of November) are normally the only time of the year during which all of the "Big Four" major professional sports leagues in the U.S. and Canada schedule games; the National Basketball Association begins its preseason and about two weeks later starts the regular season, the National Hockey League is in the first month of its regular season, the National Football League is about halfway through its regular season, and Major League Baseball is in its postseason with the League Championship Series and World Series. Days on which all four leagues play are colloquially known as a sports equinox.

American Archives Month National Adopt a Shelter Dog Month National Arts & Humanities Month National Bullying Prevention Month National Cyber Security Awareness Month National Domestic Violence Awareness Month Filipino American History Month Italian-American Heritage and Culture Month Polish American Heritage Month National Work and Family Month

United States, health-related American Pharmacist Month Celebrating All of October Dwarfism/Little People/Short Stature/Skeletal Dysplasia Awareness Dwarfism/Little People Awareness Month Eczema Awareness Month National Dental Hygiene Month National Healthy Lung Month National Infertility Awareness Month Liver Awareness Month National Lupus Erythematosus Awareness Month National Physical Therapy Month National Spina Bifida Awareness Month Sudden Infant Death Syndrome Awareness Month (United States)

United States, culinary National Pizza Month National Popcorn Poppin' Month National Pork Month National Seafood Month

Movable dates Oktoberfest celebrations (varies globally based on area) Astronomy Day: October 1 World Cerebral Palsy Day: October 6 World College Radio Day: October 7 Earth Science Week: October 9–15 See also Movable Western Christian observances See also Movable Eastern Christian observances

First Sunday Daylight saving time begins (Australia) Father's Day (Luxembourg) Grandparents Day (Queensland, Australia, United Kingdom) Teachers' Day (Belarus, Latvia, Ukraine)

First Monday Child Health Day (United States) Children's Day (Chile, Singapore) Labour Day (Australian Capital Territory, New South Wales, South Australia, Queensland, Australia) Peat Cutting Monday (Falkland Islands) Thanksgiving (Saint Lucia) World Architecture Day World Habitat Day

First Tuesday National Night Out (Florida and Texas, United States)

First Wednesday Children's Day (Chile)

First Thursday National Poetry Day (UK, Ireland)

First Friday Children's Day (Singapore) Lee National Denim Day (United States) World Smile Day

First full week Albuquerque International Balloon Fiesta (United States) Mental Illness Awareness Week (United States)

Second Sunday National Grandparents Day (Germany, Hong Kong)

Second Monday Columbus Day (United States) Indigenous Peoples' Day (Parts of the United States) Native American Day (South Dakota, United States) Fraternal Day (Alabama, United States) Health and Sports Day (Japan) Mother's Day (Malawi) Norfolk Island Agricultural Show Day (Norfolk Island) Thanksgiving (Canada) National Day (Republic of China)

Second Tuesday Ada Lovelace Day

Second Wednesday Policy Statement of Belgian Parliament (Belgium)

Wednesday of second full week in October National Fossil Day (United States)

Second Thursday World Sight Day

Second Friday Arbor Day (Namibia) World Egg Day

Second Saturday International Migratory Bird Day (Mexico, Central and South America, and the Caribbean) Home Movie Day (International observance) National Tree Planting Day (Mongolia)

Week of October 10 Fiji Week (Fiji)

Second Week of October Fire Prevention Week (Canada, United States) Fire Service Recognition Day (Canada), last day of Fire Prevention Week:

Third Sunday Teacher's Day (Brazil) Mother's Day (Argentina)

Third Monday Heroes' Day (Jamaica) Mother's Day (Argentina) Nanomonestotse (Native American communities) Boss's Day (United States, Canada, Lithuania and Romania)

Third Thursday International Credit Union Day

Third Saturday Sweetest Day (United States)

Fourth Monday Labour Day (New Zealand)

Fourth Wednesday Children's Day (Australia)

Fourth Friday Global Champagne Day

Fourth Saturday Children's Day (Malaysia) Make a Difference Day (United States)

Week of Fourth Wednesday Children's Week (Australia)

Last Monday October Holiday (Ireland)

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with October

Start with the simplest possible case. Write down what October claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to October before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about October ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of October

In research: October appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses October in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: October is common in secondary-school and first-year university syllabi. It links to neighbouring topics Months, October, so understanding it makes those chapters shorter.
In everyday life: Look for October outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study October in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what October means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain October out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is October in simple terms?

October is the 10th month of the year in the Julian and Gregorian calendars. Its length is 31 days.

Why does October matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study October?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on October.