Studies show because we follow a seven-day cycle, we actually build associations with different days of the week. With Mondays and Fridays being the strongest. Scientific research indicates: 

"They found that Monday and Fridays have a higher number of mental representations attached to them than their midweek counterparts - giving them stronger identities than Tuesdays, Wednesdays and Thursdays. Conversely, these non-descript mid-week days carry less meaning, making them more easily confused with each other.

Mondays mainly prompted negative words like 'boring', 'hectic' and 'tired' and Fridays were associated with positive words like 'party', 'freedom' and 'release'*.

Job seekers should pay particular attention to this information when it comes to trying to connect with employers on LinkedIn

Weekend Flu = the Monday morning blues.

Overall, people are not in the best moods on Mondays - and that includes recruiters! Coming off the weekend, they're dragging themselves into work and feeling a little off. That first day back to the grind is not the ideal time to ask for a status update on that job application you put in the week before. Wait a day when they're over the weekend flu and more open to these types of requests.

TGIF! It's time to gush about the employer.

This research suggests the best day to ask to connect is Friday mornings. People are wrapping up their weeks and looking forward to the weekend. It's the perfect time to send a note articulating how much you admire what the company does and why you'd love to earn a position there someday. 

P.S. - What you say matters even more then when you send it.

Choosing the right day to reach out isn't enough. It's very important you carefully word your outreach. Asking strangers for something is a huge no-no and the fastest way to get ghosted on LinkedIn. The right online networking approach requires multiple steps. Just like in face-to-face networking, you need to build trust and respect through multiple interactions.