Tuesday through Thursday reign supreme. These mid-week days hit the sweet spot: competition is moderate, CPMs drop 10-15% versus Monday and weekend spikes, and conversion intent peaks. Most advertisers hit Mondays hard and exhaust budgets by Friday.

Timing within the day matters equally. Peak hours are 8-11pm EST when people scroll during evening downtime. Business owners and B2B audiences respond best during 7-9am breakfast scrolls or 12-1pm lunch breaks. Gen Z peaks at 9pm to midnight.

Weekends typically underperform for most niches. Saturday and Sunday see CPMs jump 25-40% because advertisers fight for the same eyeballs while purchase intent drops. Exceptions include e-commerce and entertainment where weekend browsing leads to purchases.

Seasonality dominates longer arcs. Q4 November-December is premium time for shopping campaigns. January sees a resolution surge. Plan campaigns four weeks ahead of seasonal peaks and avoid blanket coverage during major holidays when costs spike 50-100%.