Predicting the visibility of the crescent Moon in February and March 2025
Many religious calendars are based, or partly based, on the phases of the Moon. These include the Catholic, Jewish and Islamic religious calendars. The dates of festivities, holidays and important events in the lunar calendar move by about 10 days every year within the Gregorian calendar.
The most important month on the Islamic calendar is the ninth month, known as Ramadan, observed by Muslims worldwide as a month of fasting (sawm), prayer, reflection and community. The Hilal, or crescent moon, marks the beginning of this period. However, there are differences of opinion on how to determine the visibility of the crescent moon. There are traditional methods for determining when the crescent should be first visible. However, some observers require an unaided sighting by eye of the crescent moon while others lean towards using astronomical calculations for assistance.
The following astronomical data concern the timing of new moons and criteria for the first visibility of the crescent moons in March and April of 2025 for Australia.
The simplest useful criterion is the lag time, or difference, between sunset and moonset. If that time is greater than 47 minutes (at the latitude of Sydney) the crescent moon should be visible to the unaided eye after sunset and before the setting of the Moon.
Another common method of prediction is to use a scheme developed by Dr Bernard Yallop of HM Nautical Office and proposed in 1997. This scheme or algorithm involves the altitude difference between the Sun and the Moon; a calculated ‘best time’ to view the Moon; and the width of the crescent. The Yallop method is applicable to any location. More details of this method and maps displaying the Moon’s visibility are available here.
Please note all dates and times listed here are for Sydney, unless otherwise stated, and times are in Australian Eastern Daylight Time (AEDT, often called ‘daylight saving time’) or Australian Eastern Standard Time (AEST). In 2025 daylight saving time at 3 am on Sunday 6 April.
The New Moon in late February and early March 2025
The new moon in February 2025 will occur at 11:45am AEDT on Friday 28 February — the last day of the month. On this day the Sun will set at 7:33 pm AEDT and the Moon will set at 7:45 pm AEDT. The lag time is only 12 minutes, so the crescent moon will not be visible to the unaided eye at Sydney’s latitude and the Yallop method concurs. Further, the Yallop method shows the crescent moon will not be visible from any location in Australia.
On Saturday 1 March the Sun will set at 7:32pm AEDT and the Moon will set at 8:15 pm AEDT. The lag time is now 43 minutes so the crescent moon again should not be visible to the unaided eye at Sydney’s latitude. The Yallop method disagrees this year and provides the following more detailed picture for Australia for 1 March.
- On Saturday 1 March if you are north and west of a line joining (approximately) Beachport (south-east coast of SA) to Narooma (south coast of NSW) the crescent Moon should be easily visible to the unaided eye.
- On Saturday 1 March if you are south and east of that region (i.e. including much of southern Victoria and anywhere in Tasmania), the crescent Moon may be visible to the unaided eye under perfect atmospheric conditions, if there is no cloud, no dust and a very clear western horizon.
- On Sunday 2 March the crescent moon should be easily visible to the unaided eye from all locations in Australia after sunset, as determined by both the lag time (the lag time is now 75 minutes) and Yallop methods.
The New Moon in late March 2025
The following new Moon occurs on Saturday 29 March at 9:58pm AEDT. This is after sunset, therefore the crescent Moon will not be visible from any location In Australia.
On the evening of Sunday 30 March, the Sun will set at 6:53pm AEDT and the Moon will set at 7:12pm AEST. The lag time is only 19 minutes so the crescent moon will not be visible to the unaided eye at Sydney’s latitude, and the Yallop method concurs.
Further, the Yallop method provides a more detailed picture for Australia on 30 March, as follows,
- On Sunday 30 March if you are north and west of a line joining (approximately) Broome (WA) to Lockhart River (Cape York, QLD) (on this line also are the mouth of the Roper river in eastern NT and Aurukun in western Cape York, QLD) the crescent Moon may be visible to the unaided eye under perfect atmospheric conditions, if there is no cloud, no dust and a very clear western horizon. This region includes Darwin.
- On Sunday 30 March if you are south and east of the above region (i.e. east of the line joining Broome to Lockhart River) but also north and west of a line joining approximately the southern end of Shark Bay (WA) to Bowen (QLD) the crescent Moon may be visible to the unaided eye but only after being found with binoculars or a telescope. To avoid irreversible eye damage please ensure the Sun has fully set before searching the western horizon for the crescent moon with your binoculars or telescope.
- On Sunday 30 March if you are south and east of the above region (i.e. of the line joining the southern end of Shark Bay to Bowen) but also north of a line joining (approximately) Jurien Bay (WA) to Yeppoon (QLD) the crescent Moon may be visible but only with binoculars or telescopes. To avoid irreversible eye damage please ensure the Sun has fully set before searching the western horizon for the crescent moon with your binoculars or telescope.
- On Sunday 30 March if you are south of the above region (i.e. of the line joining Jurien Bay to Yeppoon) the crescent moon will not be visible. This region includes Brisbane, Perth, Adelaide, Melbourne, Canberra, Sydney and Hobart.
- On Monday 31 March 31 the Sun will set at 6:52 pm AEDT and the Moon will set at 7:47 pm AEDT. The lag time is now 55 minutes and the crescent moon should be visible (at Sydney’s latitude) to the unaided eye if the western sky is clear of cloud. The Yallop method concurs. Further, the Yallop method shows that the crescent moon should be visible to the unaided eye from all locations in Australia after sunset on Tuesday 31 March.
Other locations
If you are not in Sydney but your latitude is within a degree or so of Sydney’s latitude, then the lag time method of 47 minutes should work sufficiently well for you but you will need to find the time of sunset and moonset for your location.
For Melbourne we can provide the following additional information: at the moment of sunset on Friday 28 February (8:01 pm AEDT) the Moon will be at an altitude above the horizon of 1.8-degrees and it will be 3.6-degrees to the right of the Sun. To find the moon look from the point where the Sun set and the Moon will be 3.6-degrees to the right and 1.8-degrees up from the horizon. At the moment of sunset on Saturday 1 March (exactly 8:00 pm AEDT) the Moon will be at an altitude above the horizon of 7.1-degrees and it will be 16.3-degrees to the right of the Sun. Look from the point where the Sun set look 16.3-degrees to the right then 7.1-degrees up to find the crescent Moon. On Sunday 2 March, again at the moment of sunset (7:59 pm AEDT), the Moon will now be at an altitude above the horizon of 12.1-degrees and 29.4-degrees to the right of where the Sun set.
