Entries
Rainbow Season, Fremont Cottonwoods, Venus & Jupiter, the Moon's Chesire Cat Smile
"Rainbow season" arrives with the first rains of late fall. Scattered showers are best for rainbow watching: sunlight refracting and reflecting through the raindrops causes two bows to appear: an intense circular arc at 42˚, and a bigger, but weaker …
Atmosphereic Ice Crystals, Liquidambar Trees, and Sycamores
Atmospheric ice-crystal effects are often observed, starting about this time of year, because of the frequent appearance of high clouds made of tiny bits of ice. The most familiar of these optical effects is the 22˚-radius halo, or ring, around …
Temperature Inversions, Tides, Sunrise/Sunset, and the Leonid Meteor Shower
Low-lying temperature inversions commonly occur in San Diego as winter approaches. During the night and morning hours, a meterological condition often occurs in which the normal higher-you-go-the colder-it-gets trend is reversed. At such times cold marine air lies below a …
Santa Anas, Monarchs, and Acorns
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 …
A Waxing Moon for Halloween -- Just Before Daylight Savings Time Ends
Daylight Savings Time ends this Sunday morning, November 2 at 2 a.m. With the resumption of standard time, midday (the time when the sun reaches its maximum altitude in the south part of the sky) will again be close to …
Temps, Tarantulas, and Turning Leaves
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 …
Black Oaks, Floss Silks, and Orionid
The tawny hues of the black oak tree, the floss silk tree, and the Orionid meteor show
The tawny hues of the black oak tree are just beginning to highlight the slopes of San Diego County's higher mountains. Named for the dark coloring of its bark, especially when wet, the black oak (Quercus kelloggii) is the only …
October's Beach Sand, Low Tides, Full Moon, and Venus
As the beach-going season winds down, San Diego County's coastline is padded by what is likely the deepest and widest accumulations of sand we'll see this year. Many stretches of the coastline are vulnerable to powerful waves associated with winter …
Dense Ground Fogs, Spider Webs, Chinese Flame Trees, and a Thin Crescent Moon
Dense Ground Fogs, Spider Webs, Chinese Flame Trees, and a Thin Crescent Moon
Dense ground fogs are a trademark of the onset of autumn along San Diego's coastal strip. Fog materializes during the night and early morning hours when moist marine air that has settled in valleys and low areas is chilled below …
Return of the Santa Anas
Santa Anas, Hot and Smoggy Days, Zodiacal Light
Late September signals the beginning of Santa Ana winds, which may continue intermittently through the winter. Early Santa Anas are often responsible for coastal San Diego's hottest and driest days of the year. Records show that 62 percent of the …
Fall Officially Begins
Fall officially begins at 8:44 a.m. Pacific Daylight Time on Monday, September 22 -- a good excuse to throw a "thank-God-it's-Monday-morning" party to celebrate the occasion and kick off the work week. At equinox, the sun shines directly down somewhere …
Earlier Sunsets, Coastal Sage, and a Harvest Moon
The time of sunset changes most rapidly this time of the year. This is mainly because the sun is swinging rapidly south along the ecliptic (its apparent path through the background stars). From the latitude of San Diego, the sun …
Summer Thundershowers, Chaparral, Venus, Mars, Mercury, and the Waxing Moon
Summer Thundershowers, Chaparral, Venus, Mars, Mercury, and the Waxing Moon
Summer thundershowers, having blessed the eastern margin of San Diego County with welcome, if spotty precipitation of late, have triggered a minor growth spurt among certain kinds of vegetation. In the desert, for example, the spidery ocotillo can grow an …
Warm Water Temps, Low Tides, Diminishing High Tides, and Venus
Warm water temperatures, into the 70s F over the past couple of months, won't last much longer. As fall approaches, shorter days and increasingly oblique solar radiation will mean that less and less energy will be supplied to the ocean …
Thunderstorms, Shore Birds, Jasmine, and the Milky Way
Thunderstorms have visited the Imperial Valley and parts of eastern San Diego County over the past several weeks. The seasonal arrival of moisture from the east and south, more or less typical for late summer, contributes to the greening of …
Warm Weather, Ocean Temps, Brilliant Venus, and a Full Moon
San Diego's warmest weather of the year (on average), ocean water temperatures peak, brilliant Venus, and a full moon
San Diego's warmest weather, on average, should occur in August through early September, according to statistics compiled from several decades of measurements taken near the San Diego International Airport. In an average year, coastal residents enjoy an average daily temperature …
Thunderheads, Sandpipers, Naked-Eye Planets, and the Perseid Meteor Shower
Towering thunderheads, various sandpipers, naked-eye planets, and the Perseid meteor shower
Towering thunderheads have been seen hovering over the wall of mountains east of San Diego in recent weeks. Afternoon rainshowers have already dampened Palomar, Cuyamaca and Mount Laguna on several occasions, with more of the same expected at times during …
Low Tides, Grunion, Crescent Moon, Dawn Sky
A series of extreme low tides in late July/early August can be enjoyed by true "morning people" only! Check out the local tidepool life without hordes of other people around. Thursday, July 31 features a minus 1.5-foot tide at 3:26 …
Birdwatchers, Jupiter, Fleas, and the Delta Aquarid Meteor Shower
Birdwatchers, Jupiter, Fleas, and the Delta Aquarid Meteor Shower
Birdwatchers need not despair now that the winter migrants are gone. Plenty of shore birds can be found on summer evenings in the natural coastal wetland areas of San Diego County. From south to north the publicly accessible coastal wetlands …
AKA Hay Moon, Wort Moon, Moon of Blood, Fallow Moon, and Thunder Moon
Cumulonimbus clouds, elderberry, orioles, and the full moon.
Cumulonimbus clouds, or thunderheads, are most likely to form over San Diego County's deserts and mountains during the latter part of the summer season, beginning about late July. The clouds appear by midafternoon —- often the result of moist, tropical …