Why last year's weeks do not work
Most spreadsheets forecast Ramadan by looking at the same calendar weeks of the previous year. But Ramadan starts about eleven days earlier each year on the Gregorian calendar. Over three years the whole month has moved by more than a month. A week-over-week copy puts the peak in the wrong place, twice: it misses the pre-Ramadan build-up, then over-orders after Eid when demand has already dropped.
The fix is simple to state and hard to do in Excel: align history on the lunar calendar. Compare the fourth week before Ramadan with the fourth week before Ramadan, not week 12 with week 12.
Which categories move, and when
Not every category behaves the same way. From the networks we work with, the pattern is consistent enough to plan on:
- Fragrance: the strongest lift, concentrated in the last ten days before Eid al-Fitr. Gift sets and 100 ml sizes outperform 30 ml.
- Skincare: a moderate lift in the two weeks before Ramadan, then a dip during the month, then a second lift before Eid.
- Make-up: a dip during the month, a sharp lift in the last week, driven by lipstick, eye make-up and shades that photograph well.
- Haircare and body care: little change, sometimes a dip; do not over-order on the general excitement.
- Parapharmacy: hydration, digestion and vitamins rise during the month; sun care rises when Ramadan falls in summer.
The three dates that matter
Plan orders around three dates, not one: the start of Ramadan, the last ten days, and Eid al-Fitr. Supplier lead time decides how early you must order. If your lead time is three weeks, the order for the last ten days must leave five to six weeks before Eid, when stores are still quiet. This is where gut feeling fails: the shelf looks calm, so the order is cut, and the peak arrives with nothing to sell.
Eid al-Adha, about seventy days later, brings a smaller, gift-driven lift, mostly in fragrance. Treat it as a second, shorter event.
How IRIS handles it
IRIS aligns sales history on the lunar calendar before training, so the model sees Ramadan as one event with the same shape every year, regardless of where it falls. Seasonal profiles are learned per category and per store: a boutique in a mall and a counter in a pharmacy do not peak on the same day. Order proposals integrate the supplier lead time and the case pack, so the pre-Eid order is placed while the shelf is still calm.
Planners can still adjust: a new brand, a marketing campaign or a store opening are entered as events, and the override is logged and measured.
Key takeaway
Align history on the lunar calendar, plan three dates rather than one, and place the pre-Eid order before the shelf tells you to.