@arteteco Food crops at my latitude take a year to grow, so harvest in Autumn needs to last 12 months. In more equatorial areas, where there's little seasonal variation how long do food crops take to grow?

@kevfrost I've been to the tropics, Asia and Australia, and worked in farms there, but never in staple ones. What's heavily affecting the number of harvests there is the rain, which is usually concentrated in one part of the year. What I know is that rice has 3 harvest a year at most, sweet potato has up to 2/3 depending on the rain... but that's easily searchable, and I don't see sociological connection. What else are you hiding? ;)

@arteteco just considering options for why muslim calendar (and others) is lunar while western is annual. One key reason for adopting a calendar is you guide subsistence farming. If 10th century BC Britons planned crops in January or July they would starve.

If this is less of an issue for equatorial climates, then annual calendars aren't needed and better to sync everyone to changes in moon?

@kevfrost I don't know much about how the muslim calendar developed, or calendars in general... can't be of much help, sorry :(

@arteteco no, not asking for a definitive answer; just whether my suspicion of crop planting timing differences between civilisations generated the discrepancy between lunar and solar calendar adoption