2022
Later action
National Grief Awareness Day
Declared August 30, 2022 as National Grief Awareness Day in Hidalgo County.
Evergreen date guide
What is celebrated on August 18?
See the observances and verified observance-history milestones attached to August 18. Each observance keeps its own source and date details.
Verified history
Today in history →On this date in observance history
Selected observance milestones connected to this date, based on reviewed sources.
2016
Institutional decision
National Extra Virgin Olive Oil Day
The creator-first-party launch page is dated August 18, 2016.
2015
Later action
Día de la Raza / October 12 commemoration in Honduras
Amended the 2014 framework so the combined Semana Morazánica holiday begins with the first Wednesday of October for public employees, with a separately defined period for private-…
2015
Later action
Día de las Fuerzas Armadas de Honduras
The consolidated October civic-holiday period was scheduled from the first Wednesday of October, with separate public- and private-sector timing rules.
1987
1978
Institutional decision
National POW/MIA Recognition Day
The law was approved in 1978 and the proclamation was issued before the July 18, 1979 observance.
Reviewed depth
Other in-depth guides on August 18
Source-backedFixed AnnualIn-depth guide
Bad Poetry Day
The first-party Wellcat Holidays calendar lists Bad Poetry Day on August 18 and identifies the collection as created by Thomas and Ruth Roy.
Source-backedFixed AnnualIn-depth guide
Constitution Day of the Republic of Indonesia
Indonesian government statistical-agency pages identify 18 August as Constitution Day of the Republic of Indonesia and describe it as an annual commemoration.
Source-backedFixed AnnualIn-depth guide
Long Tan Day (historical name; now Vietnam Veterans’ Day)
Australian War Memorial and Department of Veterans’ Affairs: historical Long Tan Day name; now Vietnam Veterans’ Day August 18
Source-backedFixed AnnualIn-depth guide
World Breast Cancer Research Day
The official campaign says the Dr Susan Love Foundation founded World Breast Cancer Research Day in 2021 for August 18 and documents a 2024 mission transition to Tower Cancer Research Found…
Explore the mix
All topics →Topics represented on August 18
4 observances
All observances on this date
Source-backedFixed AnnualIn-depth guide
Bad Poetry Day
The first-party Wellcat Holidays calendar lists Bad Poetry Day on August 18 and identifies the collection as created by Thomas and Ruth Roy.
Source-backedFixed AnnualIn-depth guide
Constitution Day of the Republic of Indonesia
Indonesian government statistical-agency pages identify 18 August as Constitution Day of the Republic of Indonesia and describe it as an annual commemoration.
Source-backedFixed AnnualIn-depth guide
Long Tan Day (historical name; now Vietnam Veterans’ Day)
Australian War Memorial and Department of Veterans’ Affairs: historical Long Tan Day name; now Vietnam Veterans’ Day August 18
Source-backedFixed AnnualIn-depth guide
World Breast Cancer Research Day
The official campaign says the Dr Susan Love Foundation founded World Breast Cancer Research Day in 2021 for August 18 and documents a 2024 mission transition to Tower Cancer Research Found…
How dates are selected
This page combines fixed annual dates, reusable calendar rules and year-specific dates confirmed for 2026. Variable or historical dates are included only when they are clearly supported.
Read the methodology →