Stanbridge said safety was a priority which was why organisers had been monitoring the weather carefully.
"We did make the call at 5am based on the way the weather was panning out."
Despite the weather, this year's event saw a similar number of children get involved as in previous years.
Former captain of the Silver Ferns Casey Kopua waited at the finish line to put the gold medals around the children's necks.
She said it was the true spirit of Kiwi kids to participate, regardless of the weather.
"This is my first time in Rotorua doing the TRYathlon and the weather is something definitely to remember."
Olympian Sarah Cowley-Ross was pleased to see all members of the family out and supporting their kids.
The Rotorua local was proud of the community for building strong and resilient kids who weren't afraid to "tough out" the weather.
"We need our kids to be out there being active and families need to support that."
Dylan Norvill braved the weather for the Weetbix kids TRYathlon. Photo / Stephen Parker Cooper Saunders, 7, loved the event so much he is going to participate at the TRYathlon in Mount Maunganui early next year.
The first-time TRYathlete was happy to run in the rain.
"I was in the mud and then I slipped. It was really fun."
Competing in his fourth TRYathlon, Ben De-Goeij, 12, was nervous when he saw the rain this morning but was thankful the sun came out for his race.
He enjoyed the biking stage of the event, having put some training into that section.
"I think I have gotten better at the biking. I was overlapping more people."
Ellie Smith, 7, was able to finally get involved after watching her brother, Kobe and sister Hanna compete for a few years.
Oldest sibling Kobe was slightly tired but said he hoped to make a faster time next year.
"I didn't do any training for the whole event."
Lynmore Primary School won a spot prize for having the most children entered in the event from one school.
Assistant principal Shelly Lamb was ecstatic with the large prize of Sanitarium products that she planned to give back to families that would benefit.
She said it was fantastic to see all her pupils running around and was pleased families were getting their children involved.
"It shows their perseverance, determination and their love of giving things a go."
Weet-Bix TRYathlons have been bringing communities together and keeping kids active since 1992.