The Boyzone star married Australian tv producer Storm Uechritz in an open-air ceremony in Scotland last week.
Keating told HELLO! Magazine that he knew the later Gately, who died in 2009 from an undiagnosed heart condition, was looking down to make sure the day was "perfect".
‘I know that my Mam, Steo and Storm’s granddad had a hand in making sure the weather was perfect – the one thing that was out of our hands,’ Ronan told the outlet.
Close friend and Boyzone member Keith Duffy agreed by saying, "Steo is here, that’s for sure."
At the wedding reception, Ronan, Keith and bandmates Shane Lynch and Mikey Graham joined singer Ed Sheeran on stage for a singalong.
For the couple's nuptials, Ronan's children from his marriage to Yvonne Connolly played an instrumental part.
Jack (16) acted as best man, while daughters Missy (14) and Ali (9) were Maid of Honour and flower girl respectively and the family's pug Aussie was ring bearer.
Storm wore a bespoke lace and silk dress by Australian designer Steven Khalil for the lavish celebration which was hosted in Archerfield House, Edinburgh.
The full story is in HELLO! Magazine - on newsstands now.