Observances, Festivals, and Holy Months
Modern pagans use the Wheel of the Year with four solar holidays including the equinoxes and solstices and ancient Arabs may have done the same according to Nonnosus "Most of the Saracens … consider as sacred a spot dedicated to one of the gods, gathering there twice each year. The first of these assemblies extends over a whole month and takes place about the middle of the spring, when the sun passes through the sign of Aries. The most common observance was the pilgrimage. One inscription says: "By ʾgrd son of Fdy and he returned to permanent water at the time of pilgrimage." Since the return to permanent water usually occurred in the period of ṣyf (late spring) or the beginning of qyẓ (intense heat) it is possible that the change of seasons was celebrated with a pilgrimage to a shrine. In another inscription: "By Dʾy son of Nśl and he washed when the sun was in Virgo in order to perform a pilgrimage." The sun leaves Virgo on the Fall Equinox so the author was washing in order to enter a state of ritual purity before the equinox pilgrimage. We can't really be sure whether the author was referring to the dawn or evening rising of the stars but its dawn rising would have occurred in late August before the arrival of the seasonal rains. In this case the pilgrimage was connected to rain making rituals but if the two inscriptions are about the same period then it would be the evening setting of the stars. Although we also see a mention of washing during Sagittarius.
In west and central Arabia they also had pilgrim fairs, which took place in months that were designated as holy and violence-free. According to Nonnosus as summarized by Byzantine patriarch Photius in Codex 3 of his Bibliotheca: "Most of the Saracens, both those in the Palm Grove and those beyond it and the so-called Taurenian mountains, consider as sacred a spot dedicated to one of the gods, gathering there twice each year. The first of these assemblies extends over a whole month and takes place about the middle of the spring, when the sun passes through the sign of Aries, while the other assembly lasts two months; this they celebrate after the summer solstice. In these assemblies they observe a complete peace, not only towards each other, but also towards all men living in their country. They claim that wild animals are at peace with man, and not only this, but that they are at peace with each other."
Now what about the solstices? Inscription KnGQ 4 says "he returned to permanent water at the time of pilgrimage" and pastoralists would return to permanent water and dry fodder during the summer/dry season while inscription C 4443 mentions washing during Sagittarius which ends on the Winter Solstice. So I have reason to believe the quarter points of the Wheel of the Year, the solstices and equinoxes, were observed. The solstices were the transition between the wet and dry seasons, going to temporary water and fresh herbage and then returning to permanent water and dry fodder. The equinoxes were the midpoints between them. Nonnosus tells us about a second pilgrimage period which "lasts two months; this they celebrate after the Summer Solstice." This would be a time of complete peace, and one could infer that the same was done after the Winter Solstice as well. The South Arabians also practiced pilgrimages. The Sabaeans and their allies went to the temple of Almaqah annually at the time of the summer rains. The god Ta’lab was also an object of pilgrimage at Jabal Riyam in north Sana'a. As long as these ceremonies lasted pilgrims were obliged to abstain from war and sex and they would wear ritual clothes or adornments.
For modern practitioners there are no shrines or temples to visit however you could visit places you consider sacred. The idea that certain spaces (because of their great height, beauty, lush vegetation etc) are occupied by divinities is very ancient, and there were many such places in Arabia. Sanctuaries would be open-air, the natural features of the spot were enough to distinguish it. It might be a spring with rich vegetation, a patch of forest or a shady cleft in a mountainside. Other than pilgrimages there were also seasonal offerings such as libation in this inscription: "he made a libation during the cosmical setting/full moon of Gemini."
A modern practitioner could simply follow the Wheel of the Year that many neo-Pagans use, or one could take a reconstructionist approach and use the observances mentioned below, or do both! You could also scour the database yourself to try to find other observances. Although do keep in mind that the Wheel of the Year follows the seasonal changes of a northwestern European climate and not the one in West Asia. Here's a list of the observances, make sure to double check these since I'm not that knowledgeable on astronomy:
- March 20 - April 19: Sun Passes Through Aries, Starts on the Spring Equinox
- June 21: Return to Permanent Water/Dry Season, Summer Solstice
- June 21 - August 20: After Summer Solstice, Lasts Two Months
- September 22 - October 22: Sun in Libra, Starts on the Fall Equinox
- December 22: Departure to Temporary Water/Rainy Season, Winter Solstice
- December 22 - February 22: After Winter Solstice, Lasts Two Months