| Fri, September 1 | World Peace Day (Germany) | Germany | Observance |
| Fri, September 1 | Arafat Day | Bahrain | Observance |
| Fri, September 1 | Hari Raya Haji | Singapore | National Holiday |
| Fri, September 1 | Eid-al-Adha (Feast of Sacrifice) | United arab emirates | National Holiday |
| Fri, September 1 | Eid-e-Ghorban (Feast of Sacrifice) | Iran | National Holiday |
| Fri, September 1 | Knowledge and Literature Day | Armenia | Observance |
| Fri, September 1 | Waqfat Arafat Day | Kuwait | Official Holiday |
| Fri, September 1 | Language Day Extra Holiday | Moldova | National Holiday |
| Fri, September 1 | Independence Day | Uzbekistan | Public Holiday |
| Fri, September 1 | Constitution Day | Slovakia | National Holiday |
| Fri, September 1 | Sacrifice Feast | Turkey | National Holiday |
| Fri, September 1 | Eid-al-Adha Holiday 1 | Qatar | Public Holiday |
| Fri, September 1 | Commencement Day of Eritrean Armed Struggle | Eritrea | Public Holiday |
| Fri, September 1 | Feast of the Sacrifice | Azerbaijan | Public Holiday |
| Fri, September 1 | Day of Arafah | Libya | Public Holiday |
| Fri, September 1 | Emma Nutt Day | - | Weird |
| Fri, September 1 | No Rhyme or Reason Day | - | Weird |
| Sat, September 2 | Eid-al-Adha | Multiple Countries | Multiple Types |
| Sat, September 2 | Tabaski | Multiple Countries | Public Holiday |
 |
| Sat, September 2 | Army Day | Nicaragua | Observance |
| Sat, September 2 | Eid al-Adha | Multiple Countries | Multiple Types |
| Sat, September 2 | Eid ul-Adha | Bangladesh | Public Holiday |
| Sat, September 2 | Eid al Addha | Kosovo | Official Holiday |
| Sat, September 2 | Eid al-Qurban | Afghanistan | Public Holiday |
| Sat, September 2 | Eid-al-Adha holiday | Multiple Countries | Multiple Types |
| Sat, September 2 | Eid-al-Adha Holiday 1 | United arab emirates | National Holiday |
| Sat, September 2 | Hajj Day | Maldives | Public Holiday |
| Sat, September 2 | Bakr Id/Eid ul-Adha | India | Gazetted Holiday |
| Sat, September 2 | Hari Raya Haji | Malaysia | Federal Public Holiday |
| Sat, September 2 | Feast of the Sacrifice | Multiple Countries | Multiple Types |
| Sat, September 2 | Eid-al-Adha (Feast of Sacrifice) | Multiple Countries | Multiple Types |
| Sat, September 2 | Id-ul-Adha (Feast of the Sacrifice) | Philippines | Common Local Holidays |
| Sat, September 2 | Idd ul Adha | Kenya | Public Holiday |
| Sat, September 2 | Day of the Independent City of Ceuta | Spain (Ceuta) | Local Holiday |
| Sat, September 2 | Id ul Adha | Ghana | Public Holiday |
| Sat, September 2 | Sacrifice Feast Day 2 | Turkey | National Holiday |
| Sat, September 2 | Muslim Day of Sacrifice (Idul Adha) | Indonesia | Public Holiday |
| Sat, September 2 | Kurban Bairam | Kazakhstan | Public Holiday |
| Sat, September 2 | Eid-ul-Azha Day 1 | Pakistan | Public Holiday |
| Sat, September 2 | Independence Day | Vietnam | National Holiday |
| Sat, September 2 | Eid-al-Adha Holiday | Multiple Countries | Multiple Types |
| Sat, September 2 | Kurman Ait | Kyrgyzstan | National Holiday |
| Sat, September 2 | Aid el-Kebir | - | Public Holiday |
| Sat, September 2 | Feast of the Sacrifice (day 2) | Azerbaijan | Public Holiday |
| Sat, September 2 | Eid el Hajj | Tanzania | Public Holiday |
| Sat, September 2 | Id el Kabir | Nigeria | Public Holiday |
| Sat, September 2 | Bison Ten Yell Day | - | Weird |
| Sun, September 3 | Armed Forces Day | Taiwan | Observance |
| Sun, September 3 | Eid al-Adha | Multiple Countries | Public Holiday |
| Sun, September 3 | Eid ul-Adha Day 2 | Bangladesh | Public Holiday |
| Sun, September 3 | Father's Day | Multiple Countries | Observance |
| Sun, September 3 | Eid-al-Adha holiday | Multiple Countries | Multiple Types |
| Sun, September 3 | Eid-al-Adha Holiday 2 | United arab emirates | National Holiday |
| Sun, September 3 | Feast of the Sacrifice Day 2 | Egypt | National Holiday |
| Sun, September 3 | Id-ul-Adha Day 2 | Philippines | Common Local Holidays |
| Sun, September 3 | The Feast of St Marinus and Republic Day | San marino | National Holiday |
| Sun, September 3 | Sacrifice Feast Day 3 | Turkey | National Holiday |
| Sun, September 3 | Daylight Saving Time starts | Namibia | Clock Change/daylight Saving Time |
| Sun, September 3 | Eid-ul-Azha Day 2 | Pakistan | Public Holiday |
| Sun, September 3 | Eid al-Adha holiday | Morocco | Bank Holiday |
| Sun, September 3 | Feast of the Sacrifice (day 3) | Azerbaijan | Public Holiday |
| Sun, September 3 | Id el Kabir additional holiday | Nigeria | Public Holiday |
| Sun, September 3 | Skyscraper Day | - | Weird |
| Mon, September 4 | Onam | India | Multiple Types |
| Mon, September 4 | Labor Day | Multiple Countries | Multiple Types |
| Mon, September 4 | Labour Day | Multiple Countries | Multiple Types |
| Mon, September 4 | Eid al-Adha | Multiple Countries | Public Holiday |
| Mon, September 4 | Eid ul-Adha Day 3 | Bangladesh | Public Holiday |
| Mon, September 4 | Eid-al-Adha holiday | Multiple Countries | Multiple Types |
| Mon, September 4 | Feast of the Sacrifice Day 3 | Egypt | National Holiday |
| Mon, September 4 | World Sexual Health Day | - | International |
| Mon, September 4 | Sacrifice Feast Day 4 | Turkey | Extra Public Holiday |
| Mon, September 4 | Eid-ul-Azha Day 3 | Pakistan | Public Holiday |
| Mon, September 4 | Independence Day observed | Vietnam | National Holiday |
| Mon, September 4 | Eid-al-Adha Holiday | Multiple Countries | Multiple Types |
| Mon, September 4 | Eat an Extra Dessert Day | - | Weird |
| Tue, September 5 | Ghost Festival | Taiwan | Observance |
| Tue, September 5 | Eid al-Adha | Bahrain | Public Holiday |
| Tue, September 5 | Eid ul-Adha Day 4 | Bangladesh | Optional Holiday |
| Tue, September 5 | Spirit Festival | China | Observance |
| Tue, September 5 | Eid-al-Adha holiday | Multiple Countries | National Holiday |
| Tue, September 5 | Feast of the Sacrifice Day 4 | Egypt | National Holiday |
| Tue, September 5 | Binara Full Moon Poya Day | Sri lanka | Public Holiday |
| Tue, September 5 | International Day of Charity | - | International |
| Tue, September 5 | Eid-ul-Azha Day 4 | Pakistan | Public Holiday |
| Tue, September 5 | Eid-al-Adha Holiday | Multiple Countries | National Holiday |
| Tue, September 5 | Be Late for Something Day | - | Weird |
| Tue, September 5 | Cheese Pizza Day | - | Weird |
| Tue, September 5 | Pitru Paksha starts | - | Hindu |
| Wed, September 6 | Eid al-Adha | Bahrain | Public Holiday |
| Wed, September 6 | Unification Day | Bulgaria | National Holiday |
| Wed, September 6 | Armed Forces' Day | Sao tome and principe | Public Holiday |
| Wed, September 6 | Defence Day | Pakistan | Observance |
| Wed, September 6 | Smhlolo Day (Independence Day) | Swaziland | Public Holiday |
| Wed, September 6 | Fight Procrastination Day | - | Weird |
| Wed, September 6 | Read a Book Day | - | Weird |
| Thu, September 7 | Jeune Genevois | Switzerland (Geneva) | Common Local Holidays |
| Thu, September 7 | Independence Day | Brazil | National Holiday |
| Thu, September 7 | Constitution Day | Fiji | Public Holiday |
| |
| Thu, September 7 | Victory Day | Mozambique | Public Holiday |
| Thu, September 7 | Salami Day | - | Weird |
| Fri, September 8 | The Feast of Our Lady of Victories | Malta | National Holiday |
| Fri, September 8 | Nativity of Mary | Lebanon | Observance |
| Fri, September 8 | Kosrae Liberation Day | Micronesia | Local Holiday |
| Fri, September 8 | Nativity of Our Lady | Liechtenstein | National Holiday |
| Fri, September 8 | National Day | Andorra | National Holiday |
| Fri, September 8 | Day of Asturias | Spain (Asturias) | Local Holiday |
| Fri, September 8 | Day of Extremadura | Spain (Extremadura) | Local Holiday |
| Fri, September 8 | Virgin of the Victory | Spain (Melilla) | Local Holiday |
| Fri, September 8 | International Literacy Day | - | International |
| Fri, September 8 | Independence Day | Macedonia, republic of | National Holiday |
| Fri, September 8 | Pardon Day | - | Weird |
| Sat, September 9 | Knabenschiessen | Switzerland (Zurich) | Observance |
| Sat, September 9 | German Language Day | Germany | Observance |
| Sat, September 9 | National Day | North korea | Public Holiday |
| Sat, September 9 | Children´s Day | Costa rica | Observance |
| Sat, September 9 | Eid-al-Ghadir | Iran | National Holiday |
| Sat, September 9 | Special Working Day | Moldova | Observance |
| Sat, September 9 | Day of the Victims of Holocaust and of racial violence | Slovakia | Observance |
| Sat, September 9 | Carl Garner Federal Lands Cleanup Day | United states | Observance |
| Sat, September 9 | California Admission Day | United states (California) | Local Observance |
| Sat, September 9 | Independence Day | Tajikistan | Public Holiday |
| Sat, September 9 | Teddy Bear Day | - | Weird |
| Sun, September 10 | Knabenschiessen | Switzerland (Zurich) | Observance |
| Sun, September 10 | European Heritage Days (Day of the Open Monument) | Germany | Observance |
| Sun, September 10 | Day of the Homeland | Germany | Observance |
| Sun, September 10 | St. George's Caye Day | Belize | Public Holiday |
| Sun, September 10 | Teachers' Day | China | Observance |
| Sun, September 10 | Day of the Workers in the Energy Sector | Turkmenistan | Observance |
| Sun, September 10 | Turkmen Bakhshi Day | Turkmenistan | Observance |
| Sun, September 10 | Gibraltar Day | Gibraltar | Public Holiday |
| Sun, September 10 | Repression Victims' Day | Mongolia | Observance |
| Sun, September 10 | National Grandparents Day | United states | Observance |
| Sun, September 10 | World Suicide Prevention Day | - | International |
| Sun, September 10 | Fathers' Day | Multiple Countries | Observance |
| Sun, September 10 | Children´s Day | Honduras | Observance |
| Sun, September 10 | Swap Ideas Day | - | Weird |
| Mon, September 11 | Knabenschiessen | Switzerland (Zurich) | Observance |
| Mon, September 11 | Pohnpei Liberation Day | Micronesia | Local Holiday |
| Mon, September 11 | Coptic New Year | Egypt | Observance |
| Mon, September 11 | Our Lady of Coromoto | Venezuela | Observance |
| Mon, September 11 | Gibraltar Day observed | Gibraltar | Public Holiday |
| Mon, September 11 | Ethiopian New Year | Ethiopia | Public Holiday |
| Mon, September 11 | Day of Catalonia | Spain (Catalonia) | Local Holiday |
| Mon, September 11 | Patriot Day | United states | Observance |
| Mon, September 11 | St. John the Baptist Day | Eritrea | Public Holiday |
| Mon, September 11 | Geez New Year | Eritrea | Public Holiday |
| Mon, September 11 | Election day | Norway | Flag Day |
| Mon, September 11 | Make Your Bed Day | - | Weird |
| Tue, September 12 | National Day | Cabo verde | Public Holiday |
| Tue, September 12 | Eid-al-Adha | Spain (Melilla) | Local Holiday |
| Tue, September 12 | International Day for South-South Cooperation | - | International |
| Tue, September 12 | Chocolate Milkshake Day | - | Weird |
| Tue, September 12 | National Video Game Day | - | Weird |
| Wed, September 13 | International Programmers' Day | - | International |
| Wed, September 13 | Positive Thinking Day | - | Weird |
| Wed, September 13 | Roald Dahl Day | - | Weird |
| Thu, September 14 | Holy Cross Day | - | Christian |
| Thu, September 14 | Battle of San Jacinto | Nicaragua | National Holiday |
| Thu, September 14 | Hug Your Hound Day | - | Weird |
| Fri, September 15 | Independence Day | Multiple Countries | National Holiday |
| Fri, September 15 | Restoration of Primorska to the Motherland Day | Slovenia | Observance |
| Fri, September 15 | Shout of Dolores | Mexico | Observance |
| Fri, September 15 | Day of Our Lady of Sorrows | Slovakia | National Holiday |
| Fri, September 15 | Nuestra Señora de la Bien Aparecida | Spain (Cantabria) | Local Holiday |
| Fri, September 15 | National POW/MIA Recognition Day | United states | Observance |
| Fri, September 15 | International Day of Democracy | - | International |
| Fri, September 15 | Make a Hat Day | - | Weird |
| Fri, September 15 | International Dot Day | - | Weird |
| Sat, September 16 | Independence Day | Multiple Countries | Multiple Types |
| Sat, September 16 | Malaysia Day | Malaysia | Federal Public Holiday |
| Sat, September 16 | National Heroes Day | Saint kitts and nevis | Public Holiday |
| Sat, September 16 | International Day for the Preservation of the Ozone Layer | - | International |
| Sat, September 16 | Day of Martyr Omar Al-Mokhtar | Libya | Public Holiday |
| Sat, September 16 | Collect Rocks Day | - | Weird |
| Sat, September 16 | Guacamole Day | - | Weird |
| Sun, September 17 | Vishwakarma Puja | - | Hindu |
| Sun, September 17 | Swiss federal fast | Switzerland (All Except Ge) | Observance |
| Sun, September 17 | Valentine's Day | Colombia | Observance |
| |
| Sun, September 17 | Birthday of Crown Prince Tupouto'a-'Ulukalala | Tonga | Public Holiday |
| Sun, September 17 | Day of Melilla | Spain (Melilla) | Local Holiday |
| Sun, September 17 | Constitution Day and Citizenship Day | United states | Observance |
| Sun, September 17 | National Hero Day | Angola | Public Holiday |
| Sun, September 17 | Teacher´s Day | Honduras | Observance |
| Sun, September 17 | International Country Music Day | - | Weird |
| Sun, September 17 | Wife Appreciation Day | - | Weird |
| Mon, September 18 | National Day | Chile | National Holiday |
| Mon, September 18 | Air Force Birthday | United states | Observance |
| Mon, September 18 | Constitution Day and Citizenship Day observed | United states | Observance |
| Mon, September 18 | Respect for the Aged Day | Japan | National Holiday |
| Mon, September 18 | Rice Krispie Treat Day | - | Weird |
| Mon, September 18 | National Cheeseburger Day | - | Weird |
| Tue, September 19 | Mahalaya Amavasya | - | Hindu |
| Tue, September 19 | Independence Day | Saint kitts and nevis | Public Holiday |
| Tue, September 19 | The Feast of Saint Januarius (Naples) | Italy | Local Holiday |
| Tue, September 19 | Army Day | Chile | National Holiday |
| Tue, September 19 | Foundation of the Slovak National Council Day | Slovakia | Observance |
| Tue, September 19 | National Gymnastics Day | - | Weird |
| Tue, September 19 | International Talk Like a Pirate Day | - | Weird |
| Tue, September 19 | Pitru Paksha ends | - | Hindu |
| Wed, September 20 | German World Childrens' Day | Germany | Observance |
| Wed, September 20 | Navaratri | Multiple Countries | Hindu Holiday |
| Wed, September 20 | Constitution Day | Nepal | Public Holiday |
| Wed, September 20 | Punch Day | - | Weird |
| Thu, September 21 | Navaratri begins | - | Hindu |
| Thu, September 21 | Rosh HaShanah Starts | - | Jewish |
| Thu, September 21 | Rosh Hashana | Multiple Countries | Multiple Types |
| Thu, September 21 | Independence Day | Multiple Countries | Multiple Types |
| Thu, September 21 | Rosh Hashana (New Year) | Israel | National Holiday, Hebrew |
| Thu, September 21 | Navaratri | Multiple Countries | Hindu Holiday |
| Thu, September 21 | Al-Hijra (Islamic New Year) | United arab emirates | National Holiday |
| Thu, September 21 | Ghatasthapana | Nepal | Public Holiday |
| Thu, September 21 | International Day of Peace | - | International |
| Thu, September 21 | Founder's Day | Ghana | Public Holiday |
| Thu, September 21 | Miniature Golf Day | - | Weird |
| Fri, September 22 | Hijra - Islamic New Year | - | Islamic |
| Fri, September 22 | September equinox | Multiple Countries | Season |
| Fri, September 22 | Muharram/Islamic New Year | Multiple Countries | Multiple Types |
| Fri, September 22 | German Sandwich Day | Germany | Observance |
| Fri, September 22 | Muharram | Multiple Countries | Multiple Types |
| Fri, September 22 | National Youth Day | Turks and caicos islands | Public Holiday |
| Fri, September 22 | Rosh Hashana II (New Year day 2) | Israel | National Holiday, Hebrew |
| Fri, September 22 | Muharram/New Year | Multiple Countries | Multiple Types |
| Fri, September 22 | Second day of Rosh Hashana | Argentina | Hebrew |
| Fri, September 22 | Independence Day | Multiple Countries | Multiple Types |
| Fri, September 22 | Islamic New Year | Multiple Countries | Multiple Types |
| Fri, September 22 | Amun Jadid | Philippines | Muslim, Common Local Holidays |
| Fri, September 22 | Emancipation Day | United states (Ohio) | Local Observance |
| Fri, September 22 | Native Americans' Day | United states (California) | Local Observance |
| Fri, September 22 | Muharram (Muslim New Year) | Saudi arabia | Observance |
| Fri, September 22 | Hijra New Year | Morocco | National Holiday |
| Fri, September 22 | Al-Hijra (Islamic New Year) | Nigeria | Local Holiday |
| Fri, September 22 | Hobbit Day | - | Weird |
| Fri, September 22 | Mabon | - | |
| Sat, September 23 | Rosh HaShanah Ends | - | Jewish |
| Sat, September 23 | International Celebrate Bisexuality Day | - | International |
| Sat, September 23 | Daylight Saving Time starts | Samoa | Clock Change/daylight Saving Time |
| Sat, September 23 | Autumn Equinox | Japan | National Holiday |
| Sat, September 23 | Saudi National Day | Saudi arabia | National Holiday |
| Sat, September 23 | Checkers Day | - | Weird |
| Sun, September 24 | Fast of Gedaliah | - | Jewish |
| Sun, September 24 | Republic Day | Trinidad and tobago | Public Holiday |
| Sun, September 24 | Tzom Gedaliah | Israel | Observance, Hebrew |
| Sun, September 24 | Constitutional Day | Cambodia | Public Holiday |
| Sun, September 24 | Independence Day (National Day) | Guinea-bissau | Public Holiday |
| Sun, September 24 | Armed Forces Day | Peru | Observance |
| Sun, September 24 | Our Lady of Las Mercedes | Dominican republic | National Holiday |
| Sun, September 24 | Anniversary of the failed attack on Lomé | Togo | Public Holiday |
| Sun, September 24 | Gold Star Mother's Day | United states | Observance |
| Sun, September 24 | Heritage Day | South africa | Public Holiday |
| Sun, September 24 | European Heritage Days | Austria | Observance |
| Sun, September 24 | Punctuation Day | - | Weird |
| Mon, September 25 | Queen's Birthday | Australia (Western Australia) | Common State Holiday |
| Mon, September 25 | Family & Community Day | Australia (Australian Capital Territory) | State Holiday |
| Mon, September 25 | Armed Forces Day | Mozambique | Public Holiday |
| Mon, September 25 | Heritage Day observed | South africa | Public Holiday |
| Mon, September 25 | Comic Book Day | - | Weird |
| Tue, September 26 | North Yemen Revolution Day | Yemen | Public Holiday |
| Tue, September 26 | World Day against Trafficking Persons | - | International |
| |
| Tue, September 26 | International Day for the Total Elimination of Nuclear Weapons | - | International |
| Tue, September 26 | Johnny Appleseed Day | - | Weird |
| Tue, September 26 | Love Note Day | - | Weird |
| Wed, September 27 | Maha Saptami | India | Restricted Holiday |
| Wed, September 27 | World Tourism Day | - | International |
| Wed, September 27 | Phulpati (Dashain) | Nepal | Public Holiday |
| Wed, September 27 | Meskel | Multiple Countries | Public Holiday |
| Wed, September 27 | Durga Puja begins | - | Hindu |
| Wed, September 27 | Crush a Can Day | - | Weird |
| Thu, September 28 | Teachers' Day | Taiwan | Observance |
| Thu, September 28 | Day of Bosnians | Kosovo | Observance |
| Thu, September 28 | St. Wenceslas Day | Czech republic | National Holiday |
| Thu, September 28 | Astami (Dashain) | Nepal | Public Holiday |
| Thu, September 28 | World Maritime Day | - | International |
| Thu, September 28 | World Rabies Day | - | International |
| Thu, September 28 | International Bosniaks' Day (for Bosniak community) | Macedonia, republic of | Optional Holiday |
| Thu, September 28 | Ask a Stupid Question Day | - | Weird |
| Thu, September 28 | Good Neighbor Day | - | Weird |
| Thu, September 28 | National Drink Beer Day | - | Weird |
| Fri, September 29 | Michael and All Angels | - | Christian |
| Fri, September 29 | Navaratri ends / Maha Navami | - | Hindu |
| Fri, September 29 | Boqueron Battle Victory Day | Paraguay | National Holiday |
| Fri, September 29 | Maha Navami | India | Restricted Holiday |
| Fri, September 29 | Nawami (Dashain) | Nepal | Public Holiday |
| Fri, September 29 | Daylight Saving Time ends | Mongolia | Clock Change/daylight Saving Time |
| Fri, September 29 | World Heart Day | - | International |
| Fri, September 29 | National Coffee Day | - | |
| Sat, September 30 | Dussehra | Multiple Countries | Multiple Types |
| Sat, September 30 | Yom Kippur | Multiple Countries | Multiple Types |
| Sat, September 30 | First Day of Ashura | Multiple Countries | Public Holiday |
| Sat, September 30 | Daylight Saving Time starts | Australia | Clock Change/daylight Saving Time |
| Sat, September 30 | Tassoua | Iran | National Holiday |
| Sat, September 30 | Dussehra (Maha Navami) | India | Gazetted Holiday |
| Sat, September 30 | Botswana Day | Botswana | Public Holiday |
| Sat, September 30 | Day of Achura | Algeria | Public Holiday |
| Sat, September 30 | Dashami (Dashain) | Nepal | Public Holiday |
| Sat, September 30 | Nationalization of the Roças | Sao tome and principe | Public Holiday |
| Sat, September 30 | First day of Yom Kippur (Jewish community) | Macedonia, republic of | Optional Holiday |
| Sat, September 30 | Astronomy Day | - | Weird |
| Sat, September 30 | Hot Mulled Cider Day | - | Weird |
| Sat, September 30 | National Public Lands Day | - | Weird |
