Trying to decide when to post photo updates to your “Summer 2015” album so the maximum number of people click through, comment on, and like your filtered selfies? Look no further. A new study conducted by the social media analytics firm Klout can tell you the best time and day of the week to post on Facebook and Twitter, depending where you are in the world.

The study found that posting in the late morning and early afternoons on Tuesdays and Wednesdays tends to generate the most engagement. Thursdays tend to be quiet, Fridays are quieter still, and the weekends are the quietest. On Mondays, the activity level begins to ramp up again as the work week begins and bored office workers take social media breaks.

Optimal times also depend on location. Tokyo peaks at the earliest time among cities studied, between 7 a.m. and 9 a.m. Paris has a high level of engagement once in the morning and once in the afternoon. In San Francisco, between 9 a.m. and 10 a.m. is ideal for posting. The most favorable time in New York is just before noon. London peaks the latest, with users becoming fully engaged on Twitter and Facebook only in the early afternoon. 

Thinking about posting a picture of your cute new nephew at night? Don’t even bother if you want maximum engagement from your followers and friends. While one explanation is that fewer people are online at night, another is that most likes, shares, and comments occur within a short window of time after someone posts something. Researchers of the study found the majority of reactions were within the first two hours of posting time.

Using a sample set of half a million active users and more than 25 million messages over 56 days, the report boasts a reaction gain of up to 4 percent on Twitter and 17 percent on Facebook when the recommended posting times are used.