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Evergreen date guide

What is celebrated on May 21?

See the observances and verified observance-history milestones attached to May 21. 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.

2020
First observance

International Tea Day

FAO explicitly identifies 21 May 2020 as the first observance of International Tea Day.

2018
First observance

Supply Chain Professionals Day

Contemporaneous coverage of the inaugural annual event states that the 2018 edition would fall on May 21, the third Monday in May.

2010
Institutional decision

World Hepatitis Day

WHA63.18 is dated 21 May 2010 and records adoption at the eighth plenary meeting that day.

1916
First observance

British Summer Time begins

Parliamentary committee evidence records the first UK clock advance on May 21, 1916.

About this date

What this date contains

7 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.

1 have a country-specific scope

Country-specific observances are not presented as worldwide events.

7 have in-depth guides

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

Reviewed depth

Other in-depth guides on May 21

Source-backedRule Based AnnualIn-depth guide

Global Accessibility Awareness Day

Third Thursday of May · Global / digital accessibility and inclusion awareness observance

Official GAAD and GAAD Foundation material states that Joe Devon and Jennison Asuncion launched Global Accessibility Awareness Day in 2012, that it is observed on the third Thursday of May,…

Source-backedFixed AnnualIn-depth guide

International Tea Day

21 May · United Nations / FAO international observance

A/RES/74/241

Source-backedRule Based AnnualIn-depth guide

National Notebook Day

Third Thursday in May · United States-origin stationery / notebook appreciation observance

The inaugural 2016 announcement identifies May Designs as the creator; subsequent coverage records the recurring rule as the third Thursday in May.

Source-backedFixed AnnualIn-depth guide

National Waiters and Waitresses Day

21 May · United States / hospitality-industry appreciation observance

Bar & Restaurant identifies May 21 as National Waiters and Waitresses Day in a dedicated 2014 article and in multiple hospitality promotional calendars.

Source-backedFixed AnnualIn-depth guide

Sister Maria Hummel Day

21 May · Hummel art/collector community / remembrance of Sister Maria Innocentia (Berta) Hummel

The M.I. Hummel organization records Berta Hummel’s birth on 21 May 1909; an observance reference places Sister Maria Hummel Day on the same 21 May birthday anchor.

Explore the mix

Topics represented on May 21

All topics →
Community, Causes & Advocacy 2Celebrations & Social 1Food, Drink & Hospitality 1Arts, Entertainment & Lifestyle 1Workplace, Professions & Appreciation 1Relationships & Family 1
7 observances

All observances on this date

Source-backedRule Based AnnualIn-depth guide

Global Accessibility Awareness Day

Third Thursday of May · Global / digital accessibility and inclusion awareness observance

Official GAAD and GAAD Foundation material states that Joe Devon and Jennison Asuncion launched Global Accessibility Awareness Day in 2012, that it is observed on the third Thursday of May,…

Source-backedFixed AnnualIn-depth guide

International Tea Day

21 May · United Nations / FAO international observance

A/RES/74/241

Source-backedRule Based AnnualIn-depth guide

National Notebook Day

Third Thursday in May · United States-origin stationery / notebook appreciation observance

The inaugural 2016 announcement identifies May Designs as the creator; subsequent coverage records the recurring rule as the third Thursday in May.

Source-backedFixed AnnualIn-depth guide

National Waiters and Waitresses Day

21 May · United States / hospitality-industry appreciation observance

Bar & Restaurant identifies May 21 as National Waiters and Waitresses Day in a dedicated 2014 article and in multiple hospitality promotional calendars.

Source-backedFixed AnnualIn-depth guide

Sister Maria Hummel Day

21 May · Hummel art/collector community / remembrance of Sister Maria Innocentia (Berta) Hummel

The M.I. Hummel organization records Berta Hummel’s birth on 21 May 1909; an observance reference places Sister Maria Hummel Day on the same 21 May birthday anchor.

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 →