Moonrise and Moonset Calculator: Plan Your Observation

Enter the observation date, coordinates, and correct timezone in the Moonrise and Moonset Calculator to find when the Moon reaches your local horizon. Then compare moonrise, upper transit, moonset, phase, twilight, and the real horizon at your site. A calculated time is an astronomical reference, not a guarantee that terrain, buildings, haze, clouds, or trees will permit immediate visibility.

Key Takeaways

• Moonrise and moonset depend on the date, coordinates, and time reference.
• Upper transit and altitude are often more useful than moonrise alone for detailed lunar observation.
• A civil date can contain no moonrise or no moonset even when the calculator is working correctly.
• Calculated horizon times assume a modeled atmosphere and an unobstructed horizon.
• The best observing period is the overlap between suitable sky conditions, a useful Moon position, and the target’s requirements.

The sections below turn the calculator’s times into a practical observation window.

How Do You Use the Moonrise and Moonset Calculator?

Select the date and observing location, verify the timezone, and compare the Moon’s horizon window with the hours you intend to observe.

1. Choose the Local Observation Date

Use the civil date that applies at the observing site.

This matters near midnight because the same astronomical event can appear on different calendar dates in different timezones. For a multi-night trip, calculate every night separately rather than assuming the Moon will rise a fixed number of minutes later each day.

2. Enter Accurate Coordinates

Latitude and longitude determine how the Moon’s apparent path meets the observer’s horizon.

A nearby city may be adequate for broad planning. Use the actual observing-site coordinates when timing a low Moon against a ridge, coastline, building, or photographic foreground.

Check the sign convention required by the calculator. Many astronomical services use positive values for north latitude and east longitude.

3. Verify the Timezone and Daylight-Saving Rule

An incorrect time reference can shift every displayed event.

Check whether the calculator uses:

• a named timezone;
• a fixed UTC offset;
• the timezone configured on the device; or
• Coordinated Universal Time.

A fixed UTC offset does not automatically apply a city’s historical or future daylight-saving changes. Use the offset that applies at the selected location on the selected date.

4. Read the Complete Result

When available, record:

• moonrise;
• upper transit;
• moonset;
• rise and set azimuth;
• altitude at transit;
• phase;
• illuminated fraction;
• sunset and twilight times.

The Moon Phase Calculator helps interpret illumination and waxing or waning status. The Astronomical Twilight Calculator helps identify the end of evening astronomical twilight and the beginning of morning astronomical twilight when evaluating the available dark-sky window.

5. Compare the Result with Your Session

A Moon that rises at 11:50 p.m. does not affect a session ending at 10:00 p.m.

A Moon that is technically above an ideal horizon may still be hidden by a mountain or tree line. Treat the calculation as one layer of the plan, then add weather, terrain, access, setup time, and equipment needs.

What Does Each Calculator Result Mean?

Result	Meaning	Best planning use	Important limitation
Moonrise	The predicted horizon event associated with the Moon’s apparent disk rising	Planning the earliest possible lunar appearance	Real terrain or poor visibility can delay first sight
Moonset	The corresponding horizon event while the Moon is descending	Finding the end of a lunar window or beginning of a moon-free period	A raised western horizon can hide the Moon earlier
Upper transit	The instant when the Moon’s center crosses the observer’s meridian at upper culmination	Finding when the Moon is usually highest during a visible passage at low and middle latitudes	High-latitude geometry may behave differently
Rise or set azimuth	Direction measured clockwise from true north	Choosing an open horizon or aligning a foreground	A magnetic compass requires declination correction
Altitude at transit	Angular height of the Moon’s center at transit	Determining whether transit occurs at a useful elevation	A transit can occur below the horizon
Illumination	Percentage of the apparent lunar disk lit by sunlight	Estimating brightness and visible shape	It does not alone identify waxing or waning
Phase	A named position in the lunar cycle	Estimating broad visibility patterns	Exact local times still require coordinates

Upper culmination is the higher of the Moon’s two daily meridian crossings.

How Are Moonrise and Moonset Defined?

Standard astronomical almanacs define moonrise and moonset for a level, unobstructed horizon under assumed atmospheric conditions.

In the U.S. Naval Observatory convention, the calculation uses the Moon’s center together with atmospheric refraction, apparent lunar radius, and horizontal parallax. Under normal conditions near sea level, the Moon’s upper limb then appears tangent to the horizon.

The calculation treats the Moon as a complete disk regardless of phase. For a crescent Moon, the geometric upper limb used by the calculation may therefore be dark rather than visibly illuminated.

This distinction matters because a tabulated moonrise is a reproducible astronomical event, not necessarily the moment when an observer first notices the bright crescent.

Why Can Observed Visibility Differ?

The model cannot know the exact state of:

• a mountain or ridge on the horizon;
• buildings or trees;
• cloud, smoke, dust, or haze;
• temperature and pressure near the horizon;
• the observer’s precise viewing position.

A listed rise time should therefore be treated as the ideal-horizon reference.

Which Inputs Affect the Result Most?

Input	Why it matters	Possible result of an error
Date	The Moon changes position from one day to the next	Events are calculated for the wrong lunar position
Latitude	Changes the angle at which the Moon’s path crosses the horizon	Rise, set, and transit can shift
Longitude	Connects Earth’s rotation with local time	All local clock times shift
Timezone	Converts the event into civil time	A correct event appears at the wrong hour
Daylight-saving rule	Alters local clock time where applicable	A common one-hour error
Observer height	Can affect topocentric geometry and modeled atmospheric refraction; treatment of horizon dip varies by service	Usually a small timing difference, but potentially larger during shallow high-latitude horizon crossings
Local horizon	Determines when the Moon clears real obstructions	Actual appearance differs from the ideal prediction
Atmosphere	Changes refraction and near-horizon visibility	Observed timing may differ from the table

Location is not merely a display preference. It is part of the astronomical calculation.

Original Planning Framework: The Three-Window Method

A rise-and-set table becomes useful when it is converted into three overlapping time windows.

Window 1: The Sky Window

The sky window is the period when the sky is suitable for the intended task.

A moonrise photograph may begin during civil or nautical twilight. Observing faint galaxies usually benefits from the interval after evening astronomical twilight ends. Lunar surface viewing can begin before the sky is fully dark.

Window 2: The Moon Window

The Moon window is the time when the Moon is above the ideal horizon.

For low-altitude viewing, shorten this window to account for hills, buildings, trees, haze, and atmospheric extinction.

Window 3: The Target Window

The target window is the period when the subject is correctly positioned.

A landscape photograph may require a specific lunar azimuth. A meteor-shower plan must account for the radiant and Moon together. A deep-sky target may require the Moon to be below the horizon or well separated from the target.

Goal	Required overlap
Observe lunar detail	Suitable sky + Moon above the horizon + useful altitude
Photograph moonrise	Moonrise period + open eastern horizon + correct foreground alignment
Observe faint deep-sky objects	Astronomical darkness + Moon below the horizon or well separated
Watch a meteor shower	Shower peak + usable darkness + limited lunar interference
Create a moonlit landscape	Moon above the horizon + useful phase + suitable direction
Photograph a setting crescent	Moonset period + open western horizon + useful twilight

The best session is the interval in which all necessary windows overlap.

How Do You Calculate the Overlap?

For a moon-free evening deep-sky session, define:

• Session window: the planned start and end time;
• Dark-sky window: from the end of evening astronomical twilight until morning astronomical twilight begins;
• Moon-free window: before moonrise or after moonset.

For an evening session before moonrise:

Usable start = the later of the session start and astronomical-twilight end

Usable end = the earlier of the session end and moonrise

If the usable end occurs before the usable start, the planned session contains no fully dark, pre-moonrise interval.

This rule is a scheduling method, not a brightness model. It does not account for clouds, artificial light pollution, lunar angular separation, terrain, or the gradual effect of a low Moon.

Worked Example: From Calculator Output to a Decision

The following values form a hypothetical planning example. They are not a prediction for a real date or location.

Example Inputs

• Session: 9:00–11:30 p.m.
• Astronomical twilight ends: 8:48 p.m.
• Moonrise: 9:37 p.m.
• Upper transit: 3:06 a.m.
• Moonset: 10:11 a.m.
• Phase: Waxing Gibbous
• Illumination: 68%
• Eastern horizon: Partly blocked by trees

Calculated Overlap

The session begins after astronomical twilight has ended.

• Usable start: later of 9:00 p.m. and 8:48 p.m. = 9:00 p.m.
• Usable end: earlier of 11:30 p.m. and 9:37 p.m. = 9:37 p.m.
• Fully dark, pre-moonrise interval: 37 minutes
• Remaining session after calculated moonrise: 1 hour 53 minutes

Trees may delay direct visual appearance, but the delay is specific to the site and should not be assumed from the astronomical table alone.

Observer	Best use of the example session
Deep-sky observer	Use 9:00–9:37 p.m. for the faintest targets
Lunar observer	Set up before 9:37 p.m. and observe after the Moon clears the trees
Landscape photographer	Confirm rise azimuth and foreground alignment before the event

How Does Moon Phase Relate to Rise and Set Time?

Moon phase provides a broad guide to when the Moon is likely to be above the horizon. Exact times still depend on the date, season, and location.

Phase	Broad rise pattern	Broad set pattern	Common use
New Moon	Near sunrise	Near sunset	Dark-sky planning; usually difficult to observe
Waxing Crescent	After sunrise	After sunset	Western evening crescent
First Quarter	Around midday	Around midnight	Evening lunar observation
Waxing Gibbous	Afternoon	Early morning	Visible through much of the evening
Full Moon	Around sunset	Around sunrise	Available through most of the night
Waning Gibbous	Evening	Morning	Late-night and morning observation
Last Quarter	Around midnight	Around midday	Morning lunar observation
Waning Crescent	Before sunrise	Afternoon	Eastern pre-dawn crescent

These are approximate patterns described in NASA’s Moon phase guide. Use a location-specific calculator for actual event times.

Why Is No Moonrise or Moonset Listed on Some Dates?

A blank result does not automatically indicate a calculation failure.

Successive moonrises or moonsets are often separated by roughly 25 hours rather than exactly 24 hours. As the event moves through the civil day, one local date can therefore contain no rise or no set.

The U.S. Naval Observatory rise, set, and transit service notes that this kind of gap appears approximately once every 25 days in moonrise or moonset tables.

At high latitudes, the Moon may also remain above or below the horizon for an extended period. Some tables use symbols to distinguish a skipped civil-date event from continuous visibility or continuous absence.

When an event is missing:

1. Check the previous and following dates.
2. Verify the timezone and coordinates.
3. Read the service’s symbol legend.
4. Inspect several consecutive dates at high latitude.

How Accurate Are Predicted Moonrise and Moonset Times?

Predicted times are useful for ordinary planning, but actual visibility is not perfectly predictable.

The U.S. Naval Observatory tabulates rise and set times to one-minute precision because local atmospheric variations and site conditions make extra displayed precision generally impractical. A time printed to the minute should not be interpreted as a guarantee of visibility during that exact minute.

Common Sources of Difference

• atmospheric pressure and temperature;
• haze, cloud, smoke, dust, or humidity;
• local terrain and buildings;
• inaccurate coordinates;
• timezone or daylight-saving errors;
• observer elevation;
• rounding in the displayed result.

Calculator services do not all treat observer height in the same way. Some adjust atmospheric refraction or topocentric position without applying geometric horizon dip, so height inputs should be interpreted according to the service’s documentation.

High-Latitude Limitation

At high latitudes, the Moon may cross the horizon at a very shallow angle. Small changes in atmospheric refraction, observer height, or local terrain can then shift the observed event by several minutes or determine whether the event is visible at all.

A minute-level table should therefore be treated more cautiously at high latitude than at a typical low- or mid-latitude site. The USNO discusses this limitation in its rise and set definitions.

Which Is More Useful: Moonrise, Transit, or Moonset?

The most useful event depends on the observing goal.

Goal	Primary event or value	Reason
First appearance over a landscape	Moonrise	Gives eastern-horizon timing and direction
Detailed telescopic observation	Upper transit and altitude	During an ordinary visible passage at low and middle latitudes, the Moon is usually highest near upper transit
Start of a moon-free late-night period	Moonset	Indicates when direct lunar interference ends
Setting crescent photograph	Moonset	Gives western-horizon timing and direction
All-night Full Moon planning	Rise, transit, and set	The full sequence describes the night
High-latitude observation	Altitude and azimuth table	Horizon events and culminations may have unusual relationships

During an ordinary visible passage at low and middle latitudes, upper transit usually occurs near the Moon’s greatest altitude. At high latitude, transit may occur below the horizon, may not lie midway between rise and set, and unusual geometry can produce more than one transit between horizon events.

Azimuth is measured from true north, not magnetic north. Apply local magnetic declination when using a magnetic compass.

Quick Planning Guide

Observer type	Primary value to check	Secondary checks
Casual skywatcher	Moonrise or moonset	Phase and weather
Lunar observer	Upper transit and altitude	Atmospheric steadiness
Deep-sky observer	Moonrise, moonset, and twilight	Phase and angular separation
Landscape photographer	Rise or set time and azimuth	Terrain and foreground alignment
Meteor observer	Moon altitude during the shower peak	Phase, clouds, and radiant altitude

Common Mistakes and Troubleshooting

Problem	Likely cause	Recommended action
Every event is one hour early or late	Daylight-saving mismatch	Check whether the tool uses a named timezone or fixed offset
The Moon rises on the “wrong” date	The event crosses local midnight	Compare the local date with UTC and inspect adjacent dates
The Moon is not visible at the listed time	Terrain, structures, haze, or cloud	Allow time for the Moon to clear the real horizon
The direction disagrees with a compass	The result uses true azimuth	Apply magnetic declination or use a true-north map
No rise or set is listed	The event lies outside the civil date or the Moon remains above or below the horizon	Check nearby dates and the output legend
A nearby city gives a different time	The coordinates differ	Use the actual observing site
Transit is not halfway between rise and set	High-latitude or unusual geometry	Use the listed transit and altitude directly
Full Moon does not rise exactly at sunset	The phase pattern is only approximate	Use calculated local event times

Observation Planning Checklist

• Confirm the observing-site coordinates.
• Verify the local date, timezone, and daylight-saving rule.
• Record moonrise, transit, moonset, and relevant azimuths.
• Compare the Moon window with sunset and astronomical twilight.
• Check phase, illumination, and the target’s requirements.
• Account for terrain, buildings, trees, weather, and observer elevation.
• Arrive early when framing, setup, or horizon visibility matters.

Conclusion

Moonrise and moonset define the Moon’s ideal horizon window, but the useful observing period depends on the overlap between suitable sky conditions, a useful lunar position, and the target’s requirements.

Treat the calculated minute as an astronomical reference rather than a visibility guarantee. Allow additional time for terrain, atmospheric conditions, access, framing, and equipment setup.

Frequently Asked Questions

Why Is There No Moonrise or Moonset Listed Today?

The event may fall outside the selected civil date, or the Moon may remain continuously above or below the horizon at high latitude. Check adjacent dates and the calculator’s output legend.

Does a Full Moon Always Rise Exactly at Sunset?

No. Full Moon broadly rises around sunset, but the exact local time depends on lunar geometry, date, coordinates, and the time reference.

Does the Moon Always Rise Due East?

No. Rise and set azimuths vary with lunar declination, observer latitude, and date. Use the calculated true azimuth when direction matters.

Are Moonrise and Moonset Times Exact?

They are model-based predictions for an assumed horizon and atmosphere. Actual visibility may differ because of refraction, terrain, weather, buildings, trees, and observer elevation.

Sources

1. U.S. Naval Observatory — Rise, Set, and Twilight Definitions
   Technical definitions of horizon events, transit, atmospheric refraction, apparent lunar radius, horizontal parallax, accuracy, and high-latitude limitations. Accessed July 30, 2026.

2. U.S. Naval Observatory — Rise/Set/Transit Times for Major Solar System Bodies and Bright Stars
   Rise, set, transit, azimuth, altitude, observer-height treatment, one-minute precision, blank entries, and the approximate 25-hour interval between lunar horizon events. Accessed July 30, 2026.

3. U.S. Naval Observatory — Complete Sun and Moon Data for One Day
   Location-based rise, set, transit, twilight, and lunar-phase service. Accessed July 30, 2026.

4. NASA Science — Moon Phases
   Broad relationships between lunar phases and typical rise and set patterns. Accessed July 30, 2026.