The end of summer could mean trying to squeeze in one last barbecue but Yellowjackets are showing up in parts of the Bay Are.
Experts say the change in weather have led to more Yellowjackets flying around.
This year, they’re bigger than normal and because they often build nests underground, people may stumble onto a swarm by accident.
"They may be working in the yard, they hit a nest when all of the sudden yellowjackets come out of the ground," said Nola Woods from the Contra Costa County Mosquito and Vector Control. "They can bite and sting repeatedly."
Vector Control employees say these discoveries are up 21% from this time last year. They say a mild winter most likely left more queens to birth more Yellowjackets.
Both residents and local businesses have set traps earlier in the year.
"My parents every year put out traps in the trees and the yard pretty early on in the year," said Orinda resident Brenna Lowery.
Vector Control says if you see Yellowjackets, to back away, make a map of where you found them and to contact them.