It all looked so promising at the outset. May was pleasant, June was promising. July, on the other hand, was one of the wettest on record. August has a lot of work to do. But for Ireland's ice-cream men – and women – the 'typical Irish summer' is central to business, whether fair times or foul, rain or shine. Here's to you, Mr Softee.

"The climate in Ireland is perfect for ice cream; it's not too hot and not too cold," explains Yasmin Khan, manager of Teddy's, Dun Laoghaire, Co Dublin. "When it gets too hot, soft serve is no good, because it melts too quickly. Soft serve should be able to be enjoyed, over a period of a few minutes, without it running all over your hand."

For as long as any suburban Dubliner cares to remember, Teddy's has stood at the end of Windsor Terrace overlooking Scotsman's Bay. Opened in 1950 by the original 'Teddy', Edward Jacob, it was bought by South African exile Brian Khan in the late '80s, and is now run by Yasmin, his daughter, her husband Craig, and her brothers Haniff and Brian. And like the name above the door, little has changed since the doors first opened almost 60 years ago, right down to the secret recipe that the family keeps closely guarded. "The ice cream we use is made exclusively for us, to our recipe," Yasmin explains. "It's a family secret, and at the end of the day, ice cream is ice cream, but you can tell if it's a Teddy's ice cream. Because of that, we're still really busy."

Even when it rains? "You'd be amazed how many people buy ice cream in the rain. They sit in their car and enjoy it. We also find ice cream's a really popular hangover food; you'd be amazed how busy we are on a Sunday morning. But we've had the same regulars coming here for years; the kids getting older every time."

Ice cream, after all, is a generational thing, and just as Yasmin has taken on the mantle of running Teddy's from her father – "he's semi-retired, he's always coming down and telling us what we're doing wrong" – so the family are already looking to the next generation to carry things on. "My dad has four grandsons now. We recently opened another outlet in Enniskerry, and we're hoping to open another couple by the end of the year. To be honest, in the long term, as the family grows, we'll probably need another six or eight shops!"

For Lorraine O'Toole, who also caught the ice-cream bug from her father – the only manufacturer of ice-cream vans in the country – repeated bad summers are proving harder to swallow. "The last three years have been dreadful, and there's very little money in it now. By the time you pay the county council, pay your staff and buy in your ingredients, if you don't have the weather, you don't have anything. Sometimes you might head out on a glorious morning, and it ends up lashing rain for the afternoon."

Operating out of Kilmacanogue, Co Wicklow, Lorraine operates two vans, taking in anywhere from Dun Laoghaire to Brittas and all along the Wicklow coast. And despite what you may think, she's yet to be driven mad by the same looped jingles coming out of her engine.

"You get well used to it!," she laughs. "We actually have a hundred tunes that we use for our vans; if you input a different code, it plays a different tune. For example, if we're going to a birthday party, we'll play 'Happy Birthday'. At the moment, because the football season's starting soon, we use 'Match of the Day' a lot."

And as the ice-cream business is purely seasonal – "I park up the vans at the end of September, and they stay there until St Patrick's Day" – it's always good to have one or two other elements of the business to fall back on. "I was asked one time if I'd bring a girl to her debs, so her and her friends piled in the back, and we had the jingles blaring all the way into Jury's Ballsbridge. I've done a few of them now actually, but I wouldn't consider it a major part of my business!"

Not all ice-cream vendors, of course, pride themselves on their 99s. When Image magazine ranks your homemade vanilla ice cream higher than Ben and Jerry's, people start to sit up and take notice, but for New York-born Sean Murphy, who runs Murphy's Ice Cream, based in Dingle, Co Kerry, with his brother Kieran, it's all part of their job.

"The best ice cream to me is one that you make at home, with fresh cream, fresh eggs and fresh milk," says Sean. "There's almost a seasonality aspect to it as well; the vanilla crop is going to taste slightly different every year, and the milk is going to taste different in the winter. It's all absolutely from scratch."

Having built up a following in Kerry since 2000, the brothers have since opened outlets in Killarney, in McCambridge's, Galway, in Kinsale, and six weeks ago opened an ice-cream counter in the Powerscourt Townhouse in Dublin. They also have a blog, icecreamireland.com, which features some of their winning recipes. No secrets here, then. "I'm suspicious of secret recipes," says Sean. "We're constantly trying out new flavours, seeing what works and what doesn't. There are endless possibilities to what flavour you can put in ice cream. People always want to talk about the wilder, wackier flavours, but for me, doing vanilla right is one of the hardest jobs you're likely to have. After all, if you don't get the simple things right, you might as well not be in business."

And because of his dedication to the cause – he even attended an ice-cream course in Penn State University – Sean believes there's no reason why Ireland, with Murphy's leading the charge of course, can't be acknowledged as one of the great ice-cream-producing countries of the world. "There's no reason why we can't do it; we have the best milk of anywhere in the world. And if you look at Europe as a whole, there's more ice cream consumed in Ireland than in Italy or Spain. It's nothing to do with the weather." Stick that in your 99.