Local air temperatures should be declining most rapidly during this time of year, according to more than a century of local meteorological records. With every successive week, daily maximum temperatures are declining by about 3/4°F, and daily minimum temperatures are plummeting by about 1°F. (This gradual onset of fall/winter chill is probably all but unnoticed by most newcomers from harsher climates.) By January, our mean temperature will have fallen to about 55°, from an average temperature of about 70° in August.

Leaves are beginning to turn in coastal San Diego County's riparian woodland and oak woodland habitats. In response to a relatively dry spring and summer, the summer-green crowns of willows and sycamores are already fading to yellow and brown. Beneath the oaks, the deciduous poison oak is flushing red. Some good places for autumn walks this month and next include San Clemente Canyon (Marian Bear) Park adjacent to Freeway 52, Los Penasquitos Canyon Preserve north of Mira Mesa, and Wilderness Gardens Preserve County Park east of Pala in North County.

Roaming tarantula spiders are occasionally seen this time of year crossing rural roads or marching through some of San Diego's canyon-bordering neighborhoods. Doggedly searching for a mate, a male will try to hold its course despite your best effort to deflect or hinder him. Docile in temperament, most tarantulas will tolerate gentle handling; they may bite, however, if provoked. Despite their fearsome reputation, tarantula venom is less powerful than a bee's.