Choosing a date
One of the main criteria when choosing the date for your BJC is the availability of the venue. The weather in the UK is very variable, so you can not pick a weekend with good weather 12 or more months in advance, that is just down to luck.
BJC is traditionally held in the Easter school holiday, this makes it easier for people with children or students to attend. To make this more complicated Easter changes date every year and schools in different regions have different holiday dates. Easter is on the Sunday following the full moon that follows the northern spring equinox (21 March), so Easter cannot be before 22 March or after 25 April.
The early BJCs were only two days, at Exeter (in 1990) BJC became three days, at Manchester (in 1994) BJC became 4 days and at Nottingham (in 2007) BJC became 5 days,BJC Pickering was 6 days and BJC Nottingham 2011 and BJC Darton were 7 days. Traditionally BJC ends on a Sunday, but BJC 2011, BJC 2014 and BJC 2015 ran from Friday to Thursday.
BJC 2009 had summer dates, and lovely weather, which definitely contributed to people's enjoyment of the convention. Note that August is statistically one of the wettest months in the year, so summer dates don't necessarily imply better weather.
A useful website for checking different education authorities holidays is http://www.myschoolholidays.com/
1 BJC (London) was four weeks before Easter.
8 BJCs (Exeter, Coventry, Birmingham, York, Brighton, Nottingham '11, Darton '14 & Darton '15) were the weekend before Easter.
3 BJCs (Bath, Bristol & Whitstable) were on Easter weekend.
12 BJCs (Leeds, Norwich 95, Edinburgh, Durham, Cardiff, Derby, Perth, Bodmin, Nottingham '07, Doncaster, Huddersfield & Southend) were the weekend after Easter.
3 BJCs (Manchester, Nottingham 97 & Pickering) were two weeks after Easter.
1 BJC (Norwich 09) was in August.