Here is a list of recommended marathons that cover the UK, Europe and indeed the world. I have coached people who have done all these races and they all have come back with positive feedback. A few guidelines:-
- the races are all on normal road surface
- they are all timetabled at times of the year when favourable marathon weather is likely, although it can never be guaranteed and several of them can have some occasional extremes of weather 
- they are all courses where you can set a PB; none of them would be classed as difficult or, overall, hilly,  although some do have some elements of climb and descent
- websites for these events can change as new headline sponsors come on board so I haven't put web links
- these races all have their own individual entry procedures and some have qualifying standards and/or ballots, so don't expect me to know at any given date whether a race is full up!

 I have shown in bold my subjective Top 10 for perhaps the best odds of having everything right in terms of weather and a fast course in an interesting location. I have also shown in bold six races where the slightly undulating course and the likelihood of hotter than ideal weather gives slightly reduced chance of the ideal race day scenario but these events are all still worth considering and include some of the world’s great cities  

Of course, the other big variable can be the cost to travel to and from these races and clearly someone in Southern England may have a different budget if they plan to choose Sydney rather than Abingdon or Bournemouth as their autumn marathon. However, travel and hotel costs across different parts of the UK are not always much less than a similar round trip to Europe so  it's often worth looking at some of the Euro options that combine a great fast course in an exciting city in a well organised event.
 
Nearly all races go for the same weekend each year although those in March and April can fluctuate depending on Easter dates.

Moving from subjectivity towards self-indulgence I'd mention that I won one of the listed races twice. No prizes for deducing which one
 
Jan

Still searching for Euro-friendly option. For swift Americans and jetsetters, the USA often  holds its

Championships selection race in January in either Houston or Sacramento

 Feb

Seville

Tokyo

 March

Barcelona

Rome 

April

Manchester

Brighton - AVOID

Paris

London

Rotterdam

Boston

Bungay

Taunton

Madrid

 May

Sunderland

Riga

Edinburgh

 June
Stockholm

 July/Aug

Unless you are likely to be running in a major international championship or in

Helsinki I’ll call this the marathon off season   

 Sept

Berlin

Nottingham

Sydney

 Oct
Chicago

Eindhoven

Chester

Abingdon

Liverpool

Amsterdam

Venice

York

Dublin

Frankfurt

 Nov
Florence

New York City

San Sebastian

Philadelphia

Valencia

Istanbul

 Dec