Free advice: Cool water is your new best friend this weekend in southwestern Oregon. Drink a lot of it.

Wednesday is the first day of summer, and the National Weather Service says it'll start with a sizzle.

The forecast calls for triple-digit temperatures for Medford Saturday and Sunday. A high of 102 degrees is expected Saturday, only to be one-upped by Sunday, when a 103-degree high is forecast.

The normal high temperature for those dates is about 84 degrees, according to Weather Service meteorologist Ryan Sandler, who added the agency likely will issue a heat advisory as it gets closer to the weekend. Nighttime lows in the high 50s to low 60s are expected for both nights.

"We're talking almost 20 degrees above normal," Sandler said of the daytime heat. "Usually when we're that warm this time of year, we have a heat advisory out."

The temperatures aren't expected to break any daily records. The record for June 24 in Medford is 109 degrees, while the June 25 temperature to beat is 107 degrees, weather officials said.

Klamath Falls, Roseburg and Northern California are expected to see highs in the 90s.

"It looks like we're into summer," Sandler said. "We don't see any major cool down."

The Oregon Health Authority recommends people working or playing outside drink two to four cups of water every hour. They should also wear a hat and light-colored, loose-fitting clothing and take breaks in shaded or air-conditioned areas if possible.

"Use common sense," Sandler said. "People tend to push themselves, especially if it's sports-related."

— Reach reporter Ryan Pfeil at 541-776-4468 or rpfeil@mailtribune.com. Follow him at www.twitter.com/ryanpfeil.