Moon Phase
Tonight's moon and what it means
What is it?
The moon's phase is the sunlit fraction visible from Earth, cycling every 29.5 days. It sets the night sky's brightness — full moons wash out stars but light up landscapes — and drives the strength of ocean tides.
How we measure it
Computed astronomically from today's date (synodic cycle from a reference new moon) — deterministic mathematics, labeled as computed; no external feed involved.
Phases through the cycle
- Day 0New moonDarkest skies — best stargazing; strongest (spring) tides
- Days 1–13WaxingBrightening evenings; crescent → gibbous
- Day ~15Full moonBright all night; spring tides again
- Days 16–28WaningLate-night moon; darkening evenings
Within safe range
Around new moon, skies are darkest — ideal for astronomy — while coastal tides run at their monthly extremes.
Beyond the range
Around full moon, night navigation is easiest and wildlife activity shifts, but stargazing and meteor showers wash out. Both new and full moon bring spring tides: higher highs and lower lows — relevant for coastal walks, fishing and low-lying flood risk during storms.
Precautions
- Coastal plans: spring tides near new/full moon reach further up the beach — check local tide tables.
- Storm + spring tide together raises coastal flood risk (see Flood guide).
- Stargazing and meteor showers: aim for the week around new moon.
- Night hikes are easiest in the light of a waxing gibbous to full moon.