Heat in Southern San Joaquin Valley, California

The first three days of September 1998 had much above normal temperatures for California Zones 20 and 21, the Central and Southern San Joaquin Valley. The Southern San Joaquin Valley was especially warm with humidities averaging near 30 percent in the afternoons with temperatures at or above 105 degrees F. Bakersfield had a high of 105 degrees each of the first three days with minimum temperatures only lowering to 74, 78, and 73, respectively. Warmest spots in the South Valley climbed up to 109 degrees during this same period. Two reports of heat exhaustion were received for September 2 in Bakersfield indicative of the high temperatures and high humidity combination. Central Valley temperatures were only slightly lower with readings in the 103 to 107 degree range. However overnight high minimum temperature records were established for Fresno for the first 4 days in September due to the combination of high humidities and/or cloud cover. Air quality was considered "unhealthy" in combination with the high temperatures in these two California zones.