Artemis II — Humanity Returns to the Moon
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Current Moon Phase
Coordinated Lunar Time (LTC)
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Today's Moon
The current moon phase is Waning Gibbous with 71.8% illumination, on day 19.8 of the 29.53-day synodic cycle. The moon is in ♐ Sagittarius at a distance of 404,713 km from Earth. The next full moon is on May 1, 2026.
About Coordinated Lunar Time
In April 2024, the White House directed NASA to establish Coordinated Lunar Time (LTC) by the end of 2026. Because the Moon's gravity is weaker than Earth's, general relativity predicts that clocks on the lunar surface tick approximately 56.02 microseconds faster per Earth day. Over months and years, this drift accumulates enough to cause navigation errors of hundreds of meters.
LTC will be determined by a weighted average of atomic clocks placed on the Moon — similar to how UTC is calculated on Earth. The UN's International Committee on Global Navigation Satellite Systems (ICG) established a dedicated working group in 2024 to standardize lunar timing and traceability back to UTC.
The simulated LTC shown here calculates cumulative drift from the J2000.0 astronomical epoch at a rate of +56.02µs/day and adds it to the current UTC time, giving an approximation of what a Moon-based clock would read.
In August 2024, NIST published a proposal for lunar timekeeping describing how to derive a lunar time scale from relativistic corrections to UTC. The mathematical model accounts for both the gravitational blueshift (Moon clocks run fast due to lower gravity) and velocity-dependent effects, producing the net +56.02 microseconds per day rate used on this site.
Lunar time standardization is an international effort. The Artemis Accords, signed by over 50 nations, recognize the need for interoperable systems on the Moon — and a shared time reference is foundational. Moon Time Now provides this site, a moon phase calendar, and a free API to help researchers, developers, and the space-curious explore what lunar timekeeping looks like in practice.
Frequently Asked Questions
What time is it on the Moon?
The Moon does not have an official timezone yet. NASA's proposed Coordinated Lunar Time (LTC) adds the cumulative relativistic drift (+56.02 microseconds per day) to UTC. moontimenow.com shows a live simulation of what a Moon-based clock would read.
Why does time move faster on the Moon?
Because the Moon's gravity is weaker than Earth's, general relativity predicts clocks on the lunar surface tick approximately 56.02 microseconds faster per Earth day. This is known as gravitational time dilation.
What is Coordinated Lunar Time (LTC)?
LTC is a proposed timekeeping standard directed by the White House in April 2024 for NASA to establish by the end of 2026. It will be determined by a weighted average of atomic clocks placed on the Moon, similar to how UTC works on Earth. Learn more about LTC.
How much time has the Moon gained over Earth?
Since the J2000.0 epoch (January 1, 2000), the Moon has gained over 0.5 seconds compared to Earth clocks, accumulating at a rate of 56.02 microseconds per day due to gravitational time dilation.
When will LTC be officially established?
The White House directed NASA to have a working LTC framework by the end of 2026, in time for the Artemis III crewed landing. NIST published a technical framework in August 2024, and the UN's ICG is coordinating international agreement on the standard.
How is the Moon time on this site calculated?
We apply the relativistic drift rate of +56.02 microseconds per day to UTC, accumulating from the J2000.0 epoch (January 1, 2000 at 12:00 UTC). The moon phase uses the Meeus algorithm with 25 correction terms, accurate to ~2 minutes.
What is the current moon phase?
The current moon phase is displayed at the top of this page and updated every second. For a full monthly overview, visit the Moon Phase Calendar.
Why do we need a separate time for the Moon?
Without a shared lunar time standard, navigation systems on the Moon would accumulate position errors of hundreds of meters per day. Coordinated Lunar Time ensures that spacecraft, rovers, and lunar bases can synchronize precisely. Read more.
How accurate is this lunar time clock?
The drift rate of 56.02 µs/day is based on published relativistic calculations by NASA and NIST. Our clock simulation is accurate to the millisecond for the drift component. Moon phase times are accurate to approximately 2 minutes compared to USNO data.
Can I use the Moon Time API?
Yes! Our free JSON API returns the current simulated LTC, cumulative drift, today's drift, and moon phase data. No authentication required.
Learn About Lunar Time
Artemis 2: Humanity Returns to the Moon
Launching April 1, 2026, Artemis 2 sends four astronauts around the Moon — the first crewed lunar mission in over 50 years. Here's what it means for the future of lunar time.
Artemis and the Future of Lunar Timekeeping
NASA's Artemis program is driving the need for precision timekeeping on the Moon. Here's how LTC will enable lunar navigation, communication, and future Moon bases.
From Sundials to Lunar Time: A History of Timekeeping
From ancient sundials to atomic clocks to the Moon — how humanity's quest for precise timekeeping led to Coordinated Lunar Time.
How Lunar Time Is Calculated
The technical details behind lunar time — from the J2000 epoch reference to the Meeus algorithm that calculates moon phases to within 2 minutes accuracy.