Idylllic: The beautiful cobalt blue Adriatic

The closer we drew to Lokrum, the louder the crickets became. High-pitched and incessant, like school children letting rip during an interval at the theatre, their chirruping drowned out our boat's engine noise and the slapping of waves against its bow.

We tied up to the island's concrete jetty where the din smothered not only the sea gulls' cries, but the shrill salutations of the wild peacocks and mid-air whoops from cliff-divers plummeting into the cobalt blue Adriatic.

Serenaded by the bugs' chorus – I felt as if my skin was throbbing along with them at some microsonic level – we wandered inland. We could have been a hundred miles from Dubrovnik's marble-paved Old Town, tour groups and restaurant touts, but were just a 10-minute water-taxi ride away.

Uninhabited Lokrum, part of the southern Dalmatia islands, has no roads for cars or coach drop-off points, just pedestrian paths carpeted with sun-dried pine needles. The trail we picked up from the harbour led uphill, to the eastern corner of the island and the saltwater lake the Dalmatians call Mrtvo More (Dead Sea). We squashed our bags out of sight into a crevice in the rocks, stripped down to swimwear and floated peacefully across the natural plunge pool. Until, that is, the gentle rain – which at first had melted into the surface of the lake – gathered enough pace and punch to blind us with ricocheting salt water.

After a slippery scramble across the rocks to save cameras, paperbacks and loose kuna notes, we ran through the warm, heavy rain to stand on the shoreline. Lightning flashed across the horizon where a multi-storey Mediterranean cruise ship edged towards Italy.

We watched dry, fully dressed day trippers overrun a tiny beach bar. Too late and too sodden to sneak under cover with them, we were stranded in our swimwear – the kiosk's wooden awnings diverting torrents of rainwater down to our feet. Resigned to the rain, we sipped beers as some soggy peacocks ran by.

The crickets, now conspicuous by their silence, mocked us from the trees for forgetting that in folklore, a cacophony of chirruping crickets during the day often predicts precipitation.

Footprint Croatia is available now (£13.99)