Pleasanton and the Tri-Valley are expected to see temperatures as high as 107 degrees by mid-day today, far surpassing the record high of 102 degrees for this date set at the Livermore Airport in 1958.
The Bay Area Air Quality Management District has issued its fourth consecutive Spare the Air Day for today in anticipation of high temperatures.
Today's smog alert is the ninth for the summer season, Air Quality Management District spokeswoman Kristine Roselius said.
Tonight the Tri-Valley is expected to be clear with a low temperature dipping to only 62 degrees by early morning.
Wednesday will be cooler, relatively speaking, with a high temperature of 96 degrees forecast for the Tri-Valley by mid-day. Temperatures in the 90s and high 80s are expected for the rest of the week, the Weather Service predicted.