Every year, a handful of large studies publish global best-posting-time charts, and every year agencies paste them into client decks. The charts are not wrong exactly. They are averaged across millions of accounts spanning every industry and time zone, which makes them close to useless for a specific roofing company in a specific metro.
Here is a better approach, plus reasonable starting points for when you have no data yet.
Starting points, not answers
If a client is brand new and you have nothing to work from, these are defensible opening positions for local service businesses in the US:
Facebook — Weekdays between 9am and 1pm local. Facebook's local audience skews older and checks during work breaks. Sunday evening also performs unusually well for home services, when people are thinking about the week's projects.
Instagram — Weekdays 11am to 2pm, and 7pm to 9pm. Evening is stronger for anything visual: before-and-after work, food, interiors.
LinkedIn — Tuesday through Thursday, 8am to 10am. Weekends are nearly dead for local B2B.
Google Business Profile — Timing matters least here because posts surface in search rather than a feed. Consistency beats timing.
Use these for the first month. Then throw them away.
What actually determines the right time
Three factors override any general chart.
When your client's customers are not working. A commercial HVAC company sells to facilities managers who are at a desk at 10am. A residential HVAC company sells to homeowners who look at their phone at 8pm. Same trade, opposite schedule.
When the buying trigger fires. Local service purchases are usually reactive. Someone notices a leak, gets a bill, sees a neighbor's new fence. For seasonal trades, the trigger is weather. A lawn care company in Colorado should be posting the first genuinely warm Saturday morning in March, and the exact hour matters less than the day.
When the client can actually respond. A post that generates five inquiries at 9pm and gets a reply at 11am the next day loses most of them. If your client's phone is answered 8 to 5, weight your posting toward hours where the follow-up loop can close.
That third factor is the one agencies most often skip, and it is frequently the most important.
How to find the real answer
Run a structured test rather than guessing.
Weeks 1 through 4: Post at consistent times using the starting points above. You need a stable baseline before varying anything.
Weeks 5 through 8: Shift the whole schedule two to three hours. Keep content type and quality constant so time is the only variable.
Weeks 9 through 12: Test a third window, ideally quite different — if you have tested mid-morning and mid-afternoon, try evening.
Then compare. Not likes. Compare the metrics that connect to money: profile visits, link clicks, direct messages, and calls if you can attribute them.
Engagement rate is a proxy metric and a poor one for local service. A post at 8pm getting 40 likes from people three states away is worth less than a post at 10am getting 6 likes from people in the service area.
The frequency and consistency question
Two things matter more than the hour.
Consistency. Platform algorithms reward reliable cadence. Three posts a week at the same times beats five posts clustered on Monday.
Enough volume to learn. Below eight posts a month you do not have enough data to distinguish a good time from a good post. If a client is at four posts a month, fix volume before optimizing timing.
Where the general advice breaks
Restaurants invert the standard chart. Peak windows are 11am to 1pm for lunch decisions and 4pm to 6pm for dinner. A restaurant post at 9am is arriving at the wrong moment in the decision cycle.
Emergency services — plumbers, restoration, locksmiths — should be posting at odd hours precisely because that is when problems occur. A 6am burst pipe post has a specific reader.
Weather-dependent trades should abandon the calendar entirely during transitions. The right time to post about gutter cleaning is the day after the first heavy autumn rain, whenever that lands.
Seasonal peaks override everything. In the two weeks before a peak, post more frequently and worry less about optimal hours.
What to tell clients
Clients like the timing question because it feels like a lever. Be honest about the size of the lever.
Timing accounts for a modest share of performance. Content relevance, consistency, and follow-up speed account for far more. An agency that optimizes posting times while publishing generic content is polishing the wrong thing.
The useful framing: "We will find your best windows within the first quarter using your own data. In the meantime, the bigger wins are consistency and making sure someone answers the phone when a post works."