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Evergreen date guide

What is celebrated on May 18?

See the observances and verified observance-history milestones attached to May 18. Each observance keeps its own source and date details.

Verified history

On this date in observance history

Today in history →

Selected observance milestones connected to this date, based on reviewed sources.

2017
Later action

National First Responders Day

Senators introduced a concurrent resolution supporting designation of October 28, 2017 as Honoring the Nation’s First Responders Day. Introduction is preserved as a recognition st…

1928
Institutional decision

Child Health Day

The U.S. Code historical notes identify May 18, 1928 as the date of the source joint resolution.

About this date

What this date contains

5 observances

Each observance is shown once in this view, with its own source and scope details available on the guide page.

0 repeat predictably

0 use a fixed annual date and 0 follow a reusable calendar rule.

0 are edition-specific

These dates are shown only for the year or edition that has been confirmed.

3 have a country-specific scope

Country-specific observances are not presented as worldwide events.

5 have in-depth guides

These pages include reviewed meaning, history, activities, facts and FAQs.

Reviewed depth

Other in-depth guides on May 18

Source-backedFixed AnnualIn-depth guide

Constitution and State Flag Day

18 May each year · Turkmenistan / national Constitution and State Flag observance

Current Turkmenistan government material verifies annual Constitution and State Flag Day on May 18; official historical material dates adoption of the Constitution to 18 May 1992.

Source-backedFixed AnnualIn-depth guide

Fête du Drapeau et de l’Université

18 May annually; 2025 national ceremony verified · Haiti / national flag and university observance

The Government of Haiti documented official 18 May 2025 ceremonies for the Fête du Drapeau et de l’Université and described the date’s national symbolic importance.

Source-backedFixed AnnualIn-depth guide

HIV Vaccine Awareness Day

18 May annually · United States / NIH-led HIV vaccine research awareness

NIH identifies HIV Vaccine Awareness Day (HVAD) as an annual May 18 observance honoring volunteers, communities, health professionals and scientists working on preventive HIV-vaccine resear…

Source-backedFixed AnnualIn-depth guide

National Cheese Soufflé Day

18 May · Informal food-calendar usage documented by Association of Nutrition & Foodservice Professionals chapter material

Two Association of Nutrition & Foodservice Professionals chapter calendars list National Cheese Soufflé Day on 18 May.

Source-backedRule Based AnnualIn-depth guide

Supply Chain Professionals Day

Third Monday of May (18 May in 2026) · International supply-chain profession / CSCMP-created recognition day

CSCMP’s press archive and contemporaneous trade coverage establish the April 9, 2018 launch, inaugural May 21, 2018 observance and third-Monday-in-May recurrence.

Explore the mix

Topics represented on May 18

All topics →
Civic, Remembrance & History 2Health, Wellness & Awareness 1Food, Drink & Hospitality 1Workplace, Professions & Appreciation 1
5 observances

All observances on this date

Source-backedFixed AnnualIn-depth guide

Constitution and State Flag Day

18 May each year · Turkmenistan / national Constitution and State Flag observance

Current Turkmenistan government material verifies annual Constitution and State Flag Day on May 18; official historical material dates adoption of the Constitution to 18 May 1992.

Source-backedFixed AnnualIn-depth guide

Fête du Drapeau et de l’Université

18 May annually; 2025 national ceremony verified · Haiti / national flag and university observance

The Government of Haiti documented official 18 May 2025 ceremonies for the Fête du Drapeau et de l’Université and described the date’s national symbolic importance.

Source-backedFixed AnnualIn-depth guide

HIV Vaccine Awareness Day

18 May annually · United States / NIH-led HIV vaccine research awareness

NIH identifies HIV Vaccine Awareness Day (HVAD) as an annual May 18 observance honoring volunteers, communities, health professionals and scientists working on preventive HIV-vaccine resear…

Source-backedFixed AnnualIn-depth guide

National Cheese Soufflé Day

18 May · Informal food-calendar usage documented by Association of Nutrition & Foodservice Professionals chapter material

Two Association of Nutrition & Foodservice Professionals chapter calendars list National Cheese Soufflé Day on 18 May.

Source-backedRule Based AnnualIn-depth guide

Supply Chain Professionals Day

Third Monday of May (18 May in 2026) · International supply-chain profession / CSCMP-created recognition day

CSCMP’s press archive and contemporaneous trade coverage establish the April 9, 2018 launch, inaugural May 21, 2018 observance and third-Monday-in-May recurrence.

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 →