Armed Forces Day takes place each year on the last Saturday in June.
It is an official flag flying day in Scotland.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The UK government does not designate it as an official flag flying day in the rest of the UK.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
However the Senedd Cymru flies the Armed Forces Day flag on 24 June and throughout the preceding week.
https://senedd.wales/media/hl5dtuct/foi-574-final-redacted-response-saes.pdf
The British Virgin Islands celebrate Territory Day annually on 1 July.
On this date in 1956 the islands became a separate British Overseas Territory.
The Cayman Islands celebrate Constitution Day on the first Monday of July.
It honours the island’s first written constitution, which took effect on 4 July 1959.
The Isle of Man celebrates Tynwald Day (Manx: Laa Tinvaal) annually on 5 July, unless this date falls on a Saturday or Sunday.
In this case Tynwald Day takes place on the following Monday.
Black Country Day celebrates the installation of the first practical steam engine by Thomas Newcomen (1712).
Hampshire Day takes place annually on 15 July, the Feast Day of St Swithun.
St Swithun was Bishop of Winchester (852–63) and subsequently patron saint of Winchester Cathedral.
The Birthday of HM The Queen is 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
The Birthday of HM The Queen is also 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/
Historic County Flags Day takes place annually on 23 July, giving an opportunity for individuals and organisations to show pride in their historic county.
The date commemorates the creation of the Devon Flag (2002), triggering the movement to design a modern flag for each of the UK’s historic counties.
Since 2019 (not 2020) the flags have flown together in Parliament Square, London.
Norfolk Day takes place annually on 27 July.
Local media initiated the day, first celebrated in 2018.
Buckinghamshire Day marks the origin of the Paralympic Games.
On the opening day of the London Olympics (1948), Stoke Mandeville Hospital hosted the first event ever organised for disabled athletes alongside an Olympic Games.
The Stoke Mandeville Games later became the Paralympic Games, which first took place in Rome (1960).
