Moon Phase Today in Chicago — Live Moon & Moonrise

Moonrise over open water

Few big cities get a moonrise like Chicago's. From the east lakefront the horizon is genuine open water, so the full moon climbs out of Lake Michigan with nothing in the way — no ridgeline, no treeline, just the flattest, cleanest horizon a Midwest sky offers. That is why the moon looks so large on the lakefront: a low moon over a dark, unbroken water line is the classic setting for the illusion that the disc has grown.

A shallow arc at 41.9° north

Chicago sits at about 41.9° north, and that latitude tilts the Moon's nightly path strongly toward the south. The Moon spends its hours above the horizon riding the southern sky — low in the southeast as it rises, highest as it crosses the meridian, and dropping toward the southwest as it sets. The height of that arc swings with the season: a winter full moon takes the high road, climbing close to the summer-sun altitude, while a summer full moon grazes the southern horizon for most of the night. The lake exaggerates the effect, because the eastern horizon is water rather than city.

The Moon's path is not the Sun's. The Sun stays within roughly 23.4° of the celestial equator, but the Moon's orbit is tipped about 5° to the plane of the Earth's orbit, so the Moon's own declination ranges over something closer to 28.6°. At Chicago's latitude that extra tilt is what produces the very high and very low moons you notice without quite knowing why.

A moon phase is an instant, not a date

The most common misunderstanding about moon phases is that they happen on a day. They do not. A phase is the exact moment the Moon reaches a particular angle relative to the Sun and Earth, and that moment is the same instant everywhere on the planet. What differs is the clock reading — and often the calendar date.

Chicago runs on Central Time, six hours behind UTC in winter and five hours behind during daylight saving. A phase that falls late in the UTC day can therefore land on the previous evening's date here, so the "full moon day" printed in a European almanac is not always the date the full moon arrives over Chicago. That is a feature of the time zone, not a disagreement between astronomers: the event is one instant, the dates are local labels.

The next new moon over Chicago is on 10 October 2026, and the next full moon is on 25 October 2026. Because Central Time observes daylight saving, the offset from UTC is not the same all year — another reason a phase date is worth reading for your own city rather than assuming a global one.

The cycle and its length

Phases repeat on the synodic month — the time from one new moon to the next — which averages 29.530588861 days, a little under 29 days 12 hours 44 minutes.

That figure is an average, not a fixed length. The Moon's orbit is elliptical and its speed varies, so individual cycles swing by several hours either way and a single lunation can run from about 29.2 to 29.9 days. This is why a moon calendar cannot simply be built by adding 29.530588861 days over and over, and why the phase dates on this page come from an ephemeris calculation rather than from arithmetic on a mean cycle.

When the Moon is up

Whether you can see the Moon tonight depends on where it stands in the cycle, and the rule is simple: it rises a little under an hour later each day, so its hours above the horizon slide forward through the month. Around new moon it keeps the Sun's company and is up in daylight; around full moon it is opposite the Sun and is up all night. In between, the crescent moons sit low and brief at the edges of the night.

That daily delay comes from the Moon's own motion. Against the fixed stars it slides eastward by about 13.2° a day — a full 360° turn divided by the 27.32-day sidereal month — so the Earth has to rotate a little further each night before the Moon is back in the same place over Chicago. The average delay is a little under an hour, but the exact figure swings between roughly twenty minutes and well over an hour through the month, which is why the rise pattern never repeats cleanly week to week.

What changes night to night

Over one lunation the Moon moves through the whole set. It opens as a thin waxing crescent low in the after-sunset sky, grows through first quarter — half lit, and highest around sunset — into a fat waxing gibbous, and then reaches full, when it rises as the Sun sets and stays up until morning. After full the sequence runs backwards on the other side of the sky: a waning gibbous, then last quarter highest around sunrise, then a thinning waning crescent that only shows itself before dawn. Because the whole cycle takes about 29.530588861 days, tonight's moon sits roughly a day further along than it did yesterday, which is the whole reason the phase dates keep moving.

The next new and full moons over Chicago

These are the arrival dates for Chicago (Central Time), computed from the ephemeris rather than from a mean cycle. Treat them as the date the phase is exact for this city — the evening on either side of a full moon usually looks full too.

A phase date is only half the answer. Two cities can record the same phase instant while seeing the Moon at completely different points in their sky, so if you are planning to observe, read the phase date together with how high the Moon will ride over Chicago that night — at this latitude, a low waning crescent and a high winter full moon are not remotely the same sight.

Sources and standards

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