The sun is up, the sky is blue, there's not a cloud to spoil the view, and to be honest I don't mind doing playground duty on a day like this.
"What's that you're singing, Mr Eddison?" asks Bethany.
"It's called Raining in My Heart," I reply. "It was a big hit for the legendary Buddy Holly."
She links her arm through mine. I suspect she may have ambitions to become a carer for the elderly and is using me to check whether she has a vocation for it. "Who's Buddy Holly?" she asks.
"He was the Harry Styles of his day," I tell her. "But he died in a plane crash at the age of 22."
I look up into a clear blue sky where vapour trails gently dissipate. It is reassuring to know that disaster couldn't possibly strike on a day like this. "Let's take a stroll around the playground and try not to spot any trouble," I suggest.
It is unusually calm today. Perhaps the children are too hot to fight. I relax and smile the smug, overconfident smile of a BBC weatherman prior to the Great Storm of 1987. I tell Bethany that my forecast for today's playtime is mainly trouble-free with only a small chance of a light disagreement.
But the unreliability of the British weather is nothing compared with the unreliability of a primary school playground. One moment Ryan is hanging peacefully upside down from the monkey bars; the next Nathan hits him full in the face with a water bomb. A major kerfuffle ensues. Children gather like storm clouds. Voices rumble like thunder. The threat of imminent lightning is palpable.
Amazingly, the fight is over as quickly as it started. In wrestling Nathan to the ground, Ryan's trousers are partially pulled down. His SpongeBob SquarePants boxer shorts cause squeals of amusement among the circle of innocent bystanders. By the time Bethany and I arrive on the scene both boys are laughing hysterically.
The heat is unrelenting. By mid afternoon it's too hot to work and dark enough to switch the lights on. It is a relief when a summer storm finally arrives. It begins with fat drops thudding on to the asphalt. Then the heavens open and all hell breaks loose. For a while the furious drumming of rain on our metal roof is quite scary.
So maybe this is a good time to tell the class the story of St Swithin: "He was the Bishop of Winchester and his dying wish was to be buried outdoors where the rain might fall on him. Many years later, some monks decided his remains should be dug up and reburied inside Winchester Cathedral. When they did this, a violent thunderstorm took place. This gave birth to the tradition that if it rains on St Swithin's Day it will continue to rain for the next 40 days."
"Is it St Swithin's Day today?" asks Bethany.
"Actually, today is St Ryan's Day," I tell her. "With a bit of luck the sun will be out again in no time at all."
Steve Eddison teaches at Arbourthorne Community Primary School in Sheffield