Last month, Sprout Social published its latest listings on the best times to post to each of the major social platforms, based on insights gleaned from its 20,000+ user base, in order to provide guidance as to when you should consider posting to maximize response.
But since then, a lot has changed. The COVID-19 lockdowns have lead to massive increases in social platform usage, and in some cases, significant shifts in when people are active. As such, this week, Sprout has published an update to its listings, which may help guide your revised strategy to cater to engagement changes during the pandemic.
Here's what they found - and note that all the time frames listed here are Central Time Zone (CST), though based on the data, these would be largely indicative for local time zones as well.
First off, on Facebook - in Sprout's original report, it suggested that the optimal time for Facebook engagement was Wednesday between 11am and 12pm. In the COVID-19 version, based on data gathered between March and April, it notes that the current best times to post to Facebook, based on overall engagement trends, are Monday, Wednesday and Friday from 10am to 11am.

Sprout notes that every day at 11 a.m. saw a slight peak in engagement, compared to the rest of the day, so if you're looking to maximize reach with your Facebook audience, it may be worth considering that mid-morning gap.
On Instagram, the current best times to post have similarly expanded.
As per Sprout:
"Previously, Wednesday at 11 a.m. and Friday from 10 a.m.–11 a.m. were identified as the best times to post. Now, we are seeing that out of an overall very busy span of weekday and working hours time, Monday, Tuesday and Friday at 11 a.m. and Tuesday at 2 p.m. are the best times to post on Instagram."

So on both Facebook and Instagram, your opportunities have stretched out, which would be reflective of the extra time people are spending on social platforms now that they're at home. Which may not be a great signal for workplace productivity - but either way, it seems that people are looking to a distraction in the mid-morning, which could be a key opportunity.
On Twitter, Sprout's analysts note that the best time to post hasn't varied significantly, but it has extended slightly.
"While it was previously Wednesday and Friday at 9 a.m., the current best time to post on Twitter is Friday 7–9 a.m., with 9 a.m. showing the peak of activity."

Again, that suggests that people are spending a little more time online, which expands your opportunity for connection.
And lastly, on LinkedIn, the best times have also seen a slight shuffle:
"The current best times for LinkedIn are Wednesday at 3 p.m, Thursday at 9–10 a.m. and Friday from 11 a.m.-noon."

So a little later in the week for LinkedIn, with a few options to consider.
Again, this data is not prescriptive - the only way to determine the true best time to post for your business is to experiment and see how your audience responds. It also, of course, depends on what you post, how you look to engage, what the goals of your posts are.
There are various factors at play, but these data points may help inform your initial strategy, and help you get to your posting sweet spot sooner, if you're looking for extra pointers.
You can read Sprout Social's full COVID-19 social media engagement report, which includes further insight on habitual changes and shifts, here.