FOLSOM LAKE -- A Sacramento Metropolitan Fire District spokesperson said the temperatures in many lakes and rivers was around 55 to 69 degrees Sunday.
Much of the water was recently part of the Sierra snowpack, Metro Fire Capt. Chris Vestal said.
Temperatures out of the water were in the mid-80s Sunday and are expected to reach a 2018 high in the mid-90s on Memorial Day.
"And with temperatures from 55 to 60 degrees throughout those bodies of water and with the short exposure time before there can start to be physiological effects, we want people to know that they can have those and we also want them to be as safe as possible," Vestal said.
The weekend's temperatures may be typical for this time of year, but it has been a cooler than average spring in Northern California.
At Beal's Point at Folsom Lake the beaches were packed Sunday and big crowds are expected Monday for Memorial Day. Andrew Thane was at Beal's Point Sunday and says it was nothing like a week ago.
"Now I'm getting sunburn. Last weekend it was like chills because it was so cold," Thane told FOX40.