Corey Thomas Sharpling was killed near the village of Cwmduad in Carmarthenshire, west Wales, on Saturday, Dyfed-Powys Police said.
-> Robbers push over pram containing five week old baby to steal changing bag on Yorkshire streetMr Sharpling, from Newcastle Emlyn, was one of two people to die as Callum wreaked devastation across western parts and around coastal areas on Friday and Saturday.
Elsewhere, a 38-year-old man was swept away by rough seas in Brighton, East Sussex at about 1.30 am on Saturday.
He was found in water near Brighton Palace Pier and confirmed dead by paramedics, the Maritime and Coastguard Agency said.
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Mr Sharpling's family paid tribute in a statement, saying : "We are heartbroken at the tragic loss of our beautiful son Corey. Many knew his wit, charm and sense of loyalty and we take those things with us in our hearts."
Callum eased on Sunday, with a band of rain making its way east and bringing a "reversal of fortunes" and cooler conditions.
Met Office meteorologist Luke Miall said: "Into the afternoon and evening that rain will start to pull away into the North Sea but we do see another very heavy batch of rain coming across the south and south-east.
"One or two showers to the far north west, but in between a slice of much clearer skies so a cold night to come, with some patchy frost and a few fog patches by dawn so it will be a chilly start to the new working week."
Rain will persist in the South East, while the rest of the UK should see largely dry conditions on Monday.
The better weather will come as a relief to communities hit by Storm Callum, after rivers burst their banks, homes were flooded and power supplies were wiped out.
Wales bore the brunt of the wind and downpours, and people were urged to stay away from Carmarthen after the River Towy burst its banks.
About 100 sheep were washed away in the Carmarthenshire village of Pontargothi.
Other areas in the east and south-east of the UK escaped much of the storm's wrath and enjoyed largely sunny, warm conditions.
Donna Nook in Lincolnshire reached 26.5C on Saturday, making it the warmest October day in seven years.