Summer brings the chance to see opera in some stunning surroundings far from the big cities. And if you’re a lover of medieval castles, perhaps the most spectacular of all opera venues is St Olaf’s Castle in Finland’s Savonlinna. Olavinlinna (the castle's Finnish name) needs no moat: that’s provided by the intricate patchwork of lakes around the city. The stage is set in the ancient courtyard.

© Savonlinna Opera Festival
© Savonlinna Opera Festival

The 2015 festival runs from July 3rd to August 2nd; it includes five main operas plus a “Little Magic Flute” for children. I’ll be heading there in the festival’s last week, drawn by the enticing prospect of hearing Matti Salminen singing the title role in Boris Godunov. Salminen has been described in these pages as “unwaveringly majestic”, as giving "a poignancy and musical point that I haven’t heard" or having "a glorious booming blackness", and I can't wait to hear him sing Mussorgsky's uniquely dark and richly coloured music, closer to its Russian origins than anywhere I'm likely to get any time soon. While I'm at the festival, I'll also be taking in Tosca, directed by the acclaimed Keith Warner: if ever there was an opera act that should function well in a castle courtyard, Act III of Tosca is surely it. Look out for the "overwhelming wall of sound" that can be unleashed by Elena Pankratova, who is singing the title role on July 18/24/31.

But if the dark introspection of Boris isn't for you, the beginning of the festival has a treat on the lighter side, with Lehár's The Merry Widow. In English-speaking lands, at least, operetta seems to have fallen out of favour, for reasons that I can't quite fathom: every now and then, we need something trivial to cheer us up, and for me, The Merry Widow's confection of an utterly ridiculous plot and the ultimate schmaltz of Lehár's music is irresistible. And for this particular operetta, you couldn't really pick a more appropriate company than the Vienna Volksoper, which is visiting the festival to perform it.

Also visiting the festival is Dresden State Opera, which provides the other opportunity for operatic high jinks in the shape of The Marriage of Figaro, along, of course, with sublime music such as only Mozart can write. Count and Countess Almaviva are sung by the highly rated pairing of Christoph Pohl and Rachel Willis-Sørensen. The other tragic choice (and, indeed, the other top ten rated opera) is Verdi's La traviata, conducted by Lawrence Foster.

© Savonlinna Opera Festival
© Savonlinna Opera Festival

If you need to take a break from opera every now and then (but not so far as to actually drag yourself away from music), there are three concerts to tempt your ear, ranging from the choral magic of Haydn's The Creation (away from the castle itself at Kerimäki Church) to Sonata Arctica, a heavy rock band describing themselves as "devoted to melodic metal" (a quick look at YouTube will confirm that they do what it says on the tin).

And finally, if you want to hear the operatic singing superstars of tomorrow, you might just catch one competing in the Timo Mustakallio Competition on July 19th: previous winners include Pretty Yende and Miina-Liisa Värelä.

2015 is a big year in Finland – Jean Sibelius' 150th birthday – and Savonlinna Festival will be closing in suitable style with a concert in the castle, conducted by Sibelius expert Okko Kamu and featuring the Violin Concerto and the Symphony no. 5.