Acorn dropping crescendo in Cuyamaca, Laguna, and Palomar mountains

Monarch Butterflies arrive along the California coast this month, migrating from their summer homes in the Sierra Nevada and the Rocky Mountains. Some 25 of the 260 wintering sites on the West Coast lie within San Diego County. The local sites include Presidio Park in San Diego, the UCSD campus, Quail Botanical Gardens in Encinitas, and Hosp Grove in Carlsbad.

Santa Ana Winds in San Diego County often reach their greatest intensity during November, particularly at the mountain passes, where dry air from a high-pressure area over the interior deserts swoops coastward toward a low-pressure area offshore. The subsiding air warms rapidly while it descends, resulting in 80˚–90˚ temperatures close to the coast. While passing over the mountains, though, the dry air can be surprisingly cool — 60˚ or less in the daytime.

Acorn Dropping reaches a crescendo early this month in the Cuyamaca, Laguna, and Palomar Mountains. Wiry scrub oaks, massive canyon live oaks, and the golden-leaved black oaks all contribute to the growing collection of acorns littering the ground. Acorn woodpeckers are busy stuffing acorns into the small holes they drill into the bark of pine trees. Beneath the trees, the browns of bracken fern and the reds of poison oak are among the last expressions of autumn color we’ll see in the mountains this year.

First-quarter Moon (exact at 3:46 a.m. PST). Jupiter shines brightly about 5° upper right of the Moon at dusk. Saturn shines more modestly to their right at dusk, and to their lower right later.

The above comes from the Outdoors listings in the Reader compiled by Jerry Schad, author of Afoot & Afield in San Diego County. Schad died in 2011. Planet information from SkyandTelescope.org.