The Orionid Meteor Shower
One of the year's five best annual showers, the Orionid Meteor Shower, peaks on the morning of Thursday, October 21. Unfortunately, the nearly full moon's glare will hamper observations of the meteors all night long. Despite the moon glare, and …
Ground Fog, Spider Webs, and Chinese Flame Trees
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 …
Low Tides, a Waxing Crescent Moon, and Jupiter's Satellites
October's Lowest Tides, coinciding with afternoon hours several days in a row, usher in several months of excellent tidepooling opportunities. A -0.6 foot tide occurs at 3:34pm on the Thursday, October 7. A -0.8 foot tide occurs at 4:20pm on …
Smog, Fall Migrant Birds, and Coastal Sage
The Smoggiest Days of the Year are most likely to occur during the next several weeks. Persistent temperature inversions (warmer air overlying cool marine air) are frequent this time of year. These inversions conspire with the mountainous topography of East …
The Santa Anas Come to San Diego
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 8:09pm local time on Wednesday, September 22 -- a good excuse to throw an impromptu evening party to celebrate the occasion. At equinox, the sun shines directly down somewhere on Earth's equator. At 8:09pm San Diego …
Jupiter at Opposition Today
Jupiter, the brilliant, star-like object glowing like a beacon in the eastern sky after nightfall, comes to "opposition" (180° away from the sun) on Monday, September 20. Rising at sunset and setting at sunrise, the giant planet is as close …
Sunsets and Thundershowers
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 …
Zodiacal Light and a Waxing Crescent Moon
The Waxing Crescent Moon returns to the evening sky Thursday, September 9, its fingernail-shaped thin crescent barely visible above the western horizon some ½ hour after sunset. On Friday and Saturday evenings, the fatter and brighter crescent moon lies close …
The Lowdown on Low Tides and Venus
The month's lowest tide (a not-very-low minus 0.8 foot) will occur on the morning of September 7th at 2:54am. During September the tidal range is typically minimized. Starting in mid-October, extreme negative tides will begin to occur during the afternoon …
The Beauty of Chaparral Landscape
The Chaparral, the tangled assortment of low-growing, drought-resistant, native shrubs covering most of San Diego County's lower mountain slopes, has managed to remain fairly attractive this summer. Unlike many of the scrubby natives near the coast, chaparral plants tend to …
Milky Way Viewing at Its Best
The Milky Way appears at its most glorious during August and September evenings free of moonlight (this year, the most favorable evenings occur from August 30 through September 11). You'll need to be in the mountains or the desert to …
Warm Water, Shore Birds, and Jasmine
Warm Water Temperatures, into the 70s Fahrenheit over the past several weeks, 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 waters …
Grunion Runs and a Full Moon
Grunion Runs are predicted to occur during the late evening hours (generally after 10pm and before 1am), following the nocturnal high tide, August 24 though August 26. The small, silvery grunion tend to spawn on wide, gently sloping beaches such …
Venus's Elongation and the Effect of Thunderstorms on Ocotillos
Venus, the lanternlike planet shining in the west after sunset, reaches greatest elongation from the sun on Thursday, August 19. That means the planet is illuminated from the side by the sun, as seen from Earth’s perspective. Turn a small …
Warm Air, Warm Water, and Sandpipers
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 …
The Perseid Meteor Shower, Venus, Mars, and Saturn
The Perseid Meteor Shower, the best known of the many meteor displays that return annually, will take place under optimum (moon-glare-free) conditions this year. During the hours between midnight and dawn (approximately 4:30am) on the mornings of Thursday, August 12 …
Low Tides and Grunion Rides
Extreme Low Tides early next week (the lowest levels for the month of August) occur during the wee hours of the morning. Monday, August 9 features a -1.3 foot tide at 3:27am. On Tuesday, there's a -1.3 foot low tide …
So-Called Winter Stars
Watchers of the Dawn Sky early this month will notice the bright, so-called winter stars (especially those in the constellations of Orion, Taurus, and Gemini) rising just above the rosy glow of morning twilight. The waning crescent moon is currently …
A Dance of the Planets
A "Dance of the Planets" begins in the western sky at dusk as July closes. On the evening of Saturday, July 31, notice a close pairing between Saturn (white in color) and Mars (reddish), taking place to the upper left …