Europe Day is celebrated annually on 5 May and 9 May.
The European Union designates 9 May, the anniversary of the Schuman Declaration (1950).
https://european-union.europa.eu/principles-countries-history/symbols/europe-day_en
The Council of Europe designates 5 May, the anniversary of the Council’s founding.
https://www.coe.int/en/web/portal/5-may-europe-day
Europe Day is listed on 9 May as a flag flying day by Scottish government guidance.
The European Flag is specified.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Neither date is listed as a flag flying day by UK government guidance, although the UK remains a member of the Council of Europe.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
The International Day against Homophobia, Transphobia and Biphobia is an official flag flying day only in Scotland, not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Autistic Pride Day is an official flag flying day only in Scotland, not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The birthday of the Duke of Rothesay (Prince of Wales) is listed as a flag flying day by Scottish government guidance.
The Scottish Saltire is specified.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The Birthday of the Prince of Wales is also listed as a flag flying day by UK government guidance.
The Union Flag is specified.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
Pride Edinburgh is an official flag flying day only in Scotland, not in the rest of the UK.
Its date is advised each year.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Glasgow Pride is an official flag flying day only in Scotland, not in the rest of the UK.
Its date is advised each year.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The birthday of the Princess Royal is an official flag flying day only in Scotland, not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Montmouthshire Day takes place each year on 25 September, the feast of Saint Cadoc or Cadog (born c. 497).
Cadoc was the founder of the monastery of Llancarfan, and a pioneer of Celtic Christianity in Wales.
The International Transgender Day of Remembrance honours those murdered as a result of transphobia.
It is an official flag flying day in Scotland but not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/