If today's expected high of 97 degrees isn't hot enough for you, just wait until the weekend.

If today's expected high of 97 degrees isn't hot enough for you, just wait until the weekend.

Forecasters expect highs to hover in the high 90s through Friday, then climb to 104 degrees on Saturday and peak at a searing 108 degrees on Sunday.

The culprit is a ridge of high pressure air that's preventing cool marine air from flowing into the valley. It's a pattern that develops every summer.

Temperatures in that range could be record makers. The record highs for this time of year are typically around 106 degrees, which happens to be the predicted high for Monday. That day of the year, July 27, is the hottest day of the year — at least by the law of averages. July 27 has an average high temperature of 93 degrees. It's also the day when triple-digit heat has occurred most frequently. There have been at least 20 occasions when July 27 has seen a temperature of at least 100 degrees since the National Weather Service began keeping records locally back before World War I.

Even temperatures in the 105-degree range fall well short of Medford's all time hottest days: 115 degrees on July 20, 1946, and 114 on Aug. 8, 1981.

— Bill Kettler