Bay Area Blood Moon Rises Already Eclipsed Under Fog Risk

A deep partial lunar eclipse will cover 96 percent of the full moon Thursday evening over the Bay Area, painting most of it a rusty copper while a thin northern sliver stays bright. Maximum arrives at 9:13 p.m. PDT, with the moon already rising in shadow around 7:36 p.m.

Skywatchers get hours of naked-eye viewing if the marine layer cooperates. Classic August fog and high clouds threaten the coast, pushing clearer looks inland.

The timing favors anyone who can step outside after dinner. Peak color arrives while the moon is still climbing, not hours after midnight, so the window is long enough for a short drive or a patient wait under broken cloud.

96 Percent Coverage Meets Moonrise Over the Bay

NASA calculations put greatest eclipse at 4:13 a.m. Universal Time on August 28, when 96.3 percent of the Moon’s disk sits inside Earth’s dark umbra. That converts to 9:13 p.m. Pacific on the 27th.

Local times for the San Francisco Bay Area line up closely with the global clock. Partial eclipse begins at about 7:33 p.m., minutes before moonrise near 7:38 p.m. The moon climbs already bitten by shadow. Maximum hits at 9:12 or 9:13 p.m. with the moon about 17 degrees up. Partial phase ends near 10:51 or 10:52 p.m.

The full sequence from penumbral start to finish runs 5 hours and 38 minutes overall. The dramatic umbral bite lasts 3 hours and 18 minutes. Magnitude reaches 0.930, meaning 93 percent of the moon’s diameter sits in the umbra; the area figure of 96 percent better matches what eyes see.

That gap between diameter and area matters at the eyepiece. A thin bright chord along the north rim still holds roughly four percent of the disk, yet the darkened bulk dominates the view. Casual watchers often describe the scene as nearly total even though the formal class remains partial.

No special glasses are required. Lunar eclipses stay safe for direct viewing, binoculars or backyard telescopes.

Because the moon rises already inside the umbra, early stages look dimmer than a normal full moon. Brightness recovers only as the disk climbs and more of the copper face clears the horizon haze. The altitude gain from moonrise to maximum, roughly 17 degrees, is what turns a low, muted disk into a clear target.

Copper Glow Hinges on Atmospheric Soot

The red or orange tint comes from sunlight bent through Earth’s atmosphere and scattered into the umbra. Blue wavelengths get stripped away, leaving longer reds and oranges, much like a sunset stretched across the moon.

Andrew Fraknoi, a retired astronomy professor who taught at San Francisco State University, told KQED the exact shade depends on the “sooty-ness” of the air. Fire smoke, air quality, volcanic ash and cloud cover all change how much light filters through. Cleaner air can produce a brighter copper. Heavier aerosols deepen the rust or even mute the glow.

• Cleaner air: brighter copper tones
• Fire smoke or heavy aerosols: deeper rust or muted glow
• Volcanic ash and thick cloud: further dimming of the filtered light
• Local high cloud: can veil color even when the umbra is well placed

Nature, every once in a while, likes to put on a little show for us. It reminds us that we’re part of a much larger universe.

Gerald McKeegan, astronomer, Chabot Space & Science Center

McKeegan of the Oakland center described the view at peak: almost entirely red with “just a little sliver up at the north part of the moon” still lit. That remaining bright edge keeps the event partial rather than total, yet the depth makes it look nearly complete to casual watchers.

The northern sliver is a geometric leftover. Earth’s umbra does not quite cover the full disk at this node, so a narrow arc stays outside the darkest shadow and keeps reflecting direct sunlight. That contrast, dark copper against a bright rim, is what many observers remember longest.

This eclipse belongs to Saros series 138. The previous member arrived in August 2008. The next follows in September 2044.

Members of the same Saros share similar geometry, which is why the 2008 event and this week’s deep partial feel related, and why 2044 will again favor a heavy umbral bite rather than a shallow graze.

Fog Splits Coastal Views From Inland Gaps

National Weather Service meteorologist Roger Gass told KQED that Thursday night looks mostly cloudy across much of the region, with the usual low-lying fog covering large parts of the Bay. High clouds can add another layer of obstruction even where fog thins.

Clearer chances improve farther east and inland. Gass pointed to Livermore, Concord, San Mateo and San José as spots where clouds may arrive later. Higher ground in the East Bay hills, Sonoma or Napa elevations, and places east of the Diablo Range often escape the marine layer longer.

• Coastal San Francisco and immediate shoreline: highest fog and low-cloud risk
• East Bay inland valleys and hills: better windows, later cloud arrival
• South Bay and Peninsula higher spots: mixed but often improved over the city
• Farther inland or mountain edges: strongest odds of sustained clear sky

Meteorologist takes circulating on X underscored the same split. Clear skies look solid across much of the Midwest and Plains while coastal California, the Pacific Northwest and parts of the Rockies carry elevated cloud risk. The hours-long partial phase gives watchers time to drive a short distance or wait for gaps if the forecast holds.

Southern California generally posts better odds of open sky than the Bay, according to National Weather Service notes from Los Angeles.

The practical choice is simple. Stay near the water and accept a higher chance of gray. Move a few ridgelines inland and the same three-hour umbral window becomes far more usable. Gaps can open and close quickly under August marine air, so a flexible plan beats a fixed shoreline spot.

Chabot Turns the Oakland Hills Into a Deck

The Chabot Space & Science Center hosts a public watch party from 7 to 10 p.m. Tickets run $24 for adults and $19 for kids; members enter free. The evening starts indoors in Studio 3 with live commentary and a stream of the early stages from clearer eastern sites. Once the moon rises high enough, the group moves to the observation deck for telescopes and naked-eye viewing.

McKeegan noted first good visibility often arrives around 8:15 p.m. as the moon gains altitude and brightness improves. Peak drama sits at 9:13 p.m. Staff will explain the geometry while the umbra deepens and then retreats.

Fraknoi highlighted one practical plus for West Coast families: the early evening timing lets school-age kids watch without a late bedtime. It is the first lunar eclipse unfolding at a convenient hour for the coast since September 2024.

The indoor-to-deck handoff matches the sky itself. Early partial stages can look washed out low in the east, so a streamed feed from clearer ground fills the gap. By the time the group steps outside near 8:15 p.m., the disk is higher, the copper stronger, and telescopes more useful.

Related skywatching this month included a crescent moon and Venus pairing visible after greatest elongation, another reminder that summer evenings reward simple outdoor looking.

The Long Wait Until June 2029

Bay Area residents saw a total lunar eclipse in early March 2026, but it peaked around 3:33 a.m., so many slept through the full blood-moon phase. Thursday’s deep partial offers the next strong evening opportunity.

The next total lunar eclipse visible from the Bay Area arrives on the night of June 25-26, 2029. Timeanddate data for San Francisco shows maximum shortly after moonrise that evening, with totality lasting well over an hour. Until then, partials and penumbrals fill the calendar, including events in 2027 and 2028 that offer less coverage.

1. March 2026: Total eclipse, peak after midnight, many missed it
2. August 27-28 2026: Deep partial, 96 percent, convenient evening hours
3. August 2027: Penumbral only
4. January 2028: Partial
5. December 2028: Partial locally (total elsewhere)
6. June 2029: Next total visible in the Bay

McKeegan called this week’s event the one to catch for that reason. The geometry delivers nearly total coverage without requiring an all-nighter.

Between now and mid-2029 the calendar still offers lunar eclipses, yet none combine this depth of umbral coverage with early-evening hours for the Bay. That pairing is what makes Thursday stand out on a multi-year list.

NASA’s Lunar Reconnaissance Orbiter continues returning detailed surface data; recent LRO images of lunar craters doubled as practice for planetary defense studies, showing how eclipse seasons sit inside a broader program of moon science.

Why the Northern Sliver Still Matters

The bright northern edge is small, yet it sets the official class of the eclipse. Because that rim never enters the umbra, the event stays partial even while 96 percent of the disk goes dark. Magnitude 0.930 on the diameter scale and the 96.3 percent area figure both describe the same near-miss geometry.

For observers the sliver does more than keep a label honest. It supplies contrast. Copper against a still-lit chord is easier to notice than a fully darkened disk under light pollution or thin cloud. Binoculars make the boundary sharp; a small telescope shows the umbra’s edge sliding across familiar maria.

McKeegan’s description of “just a little sliver up at the north part of the moon” matches what the tables already show: at maximum the moon is high enough for that detail to read clearly if the sky is open. The same geometry that denies totality also hands casual watchers a built-in reference line.

When the umbra finally pulls away after 10:51 p.m., the sliver widens into a normal bright limb and the copper fades. That retreat is as much part of the show as the deepening that came before.

Simple Ways to Spot the Sliver and Shadow

Find an open eastern to southeastern horizon. The moon rises already darkened, so low buildings or trees can block the early stages. Higher ground or a waterfront with a clear sightline helps.

• Start looking near 8 p.m. once the moon clears the horizon and gains height
• Use binoculars for the copper tones and the sharp umbra edge; a small telescope reveals more surface detail
• Photograph with a phone on a tripod or steady surface; longer exposures capture the red without special filters
• Dress for cool marine air even if inland spots stay warmer
• Check a live cloud map or satellite loop in the hour before peak if fog builds

About 3.3 billion people worldwide can see at least some of the partial phase, and nearly a billion can watch the entire eclipse from start to finish, according to population overlays on the visibility maps. North and South America sit in the prime zone. Western Europe and western Africa catch it before dawn or moonset.

If local clouds win, several observatories plan livestreams, including options from Griffith Observatory in Southern California that run past midnight.

The long umbral window, more than three hours, means a brief fog bank need not end the night. Many watchers will see the bite form, lose it to cloud, then recover color again before partial phase ends near 10:52 p.m.

How Far the Eclipse Reaches Around the World

Population maps place roughly 3.3 billion people under at least part of the partial phase and nearly a billion under the full sequence. The Americas hold the prime evening seats. Western Europe and western Africa see the later stages before dawn or before the moon sets.

That global spread follows from the same geometry that sets Bay Area clock times. When greatest eclipse falls at 4:13 a.m. Universal Time, evening watchers in Pacific daylight time and overnight watchers farther east are looking at one continuous shadow track.

Local weather still decides the view. Midwest and Plains skies are favored for clarity, while coastal California, the Pacific Northwest and parts of the Rockies carry higher cloud risk. Southern California’s better odds, noted by National Weather Service offices in Los Angeles, give a nearby backup for anyone willing to travel or to lean on a livestream.

The moon will leave the umbra before midnight and finish the faint penumbral phase around 12:01 a.m. Friday. By then the full disk returns, still bright under the late-summer sky if the fog has not sealed the view.

For one evening the geometry and the atmosphere meet. Whether the Bay gets the full copper performance or only broken glimpses through gaps, the next comparable total waits three years.