World Hydrography Day

World Hydrography Day (international)

World Humanist Day

World Humanist Day (Humanism)

Fête de la Musique

Solstice-related observances (see also June 20):
Fête de la Musique

Willkakuti

Solstice-related observances (see also June 20):
Willkakuti, an Andean-Amazonic New Year (Aymara)

We Tripantu

Solstice-related observances (see also June 20):
We Tripantu, a winter solstice festival in the southern hemisphere. (Mapuche, southern Chile)

Public holidays in Greenland

Solstice-related observances (see also June 20):
National Day (Greenland)

International Surfing Day

Solstice-related observances (see also June 20):
International Surfing Day

Day of Private Reflection

Solstice-related observances (see also June 20):
Day of Private Reflection (Northern Ireland)

National Indigenous Peoples Day

National Indigenous Peoples Day (Canada)

International Day of Yoga

International Yoga Day (international)

Go Skateboarding Day

Go Skateboarding Day

Father's Day

Father's Day (Egypt, Lebanon, Jordan, Syria, Uganda, Pakistan, United Arab Emirates)

Public holidays in Togo

Day of the Martyrs (Togo)

June 21 (Eastern Orthodox liturgics)

Christian feast day:
June 21 (Eastern Orthodox liturgics)

Onesimos Nesib

Christian feast day:
Onesimos Nesib (Lutheran)