I've visited Iona twice and have only ever seen it in bright warm sunshine. The beaches have beautiful white sand and the rebuilt abbey and the whole island is a peaceful place.
It is said that Columba had to leave the Irish mainland under a bit of a cloud. According to tradition, as an abbott he was involved in a quarrel with Finian, the abbott of Movilla Abbey. Columba had visited him and copied the manuscript of a Psalter held in Movilla Abbey, intending to keep it. St Finian disputed his right to keep it - and that's how the quarrel started. This led to a battle with many deaths - probably the first battle ever over a copyright dispute.You can read about it the article The Battle of the Books.
Thanks to some friendly intervention, Columba was not excommunicated. Instead he was either sent into exile or chose it voluntarily. With 12 companions he crossed the sea in a coracle to what is now Scotland and became one of the most significant Christian missionaries for Scotland. On the island of Iona he founded an abbey which became a centre of literacy, education and a school for missionary monks. It continues today as a centre of Christian community. See The Iona Community here.
As it's St Columba's Day today, here is a prayer attributed to him:
Be thou a bright flame before me,
Be thou a guiding star above me,
be thou a smooth path below me,
be thou a kindly shepherd behind me,
today - tonight - and for ever.
Image Credit: Peter Amsden on geograph.org.uk, cc License