The First Minister told MSPs she hoped to allow all non-essential retail to return, with hospitality premises allowed to serve alcohol outdoors and food only indoors, from that date.
Further easing of outdoor socialising restrictions will also happen, with six people from three households allowed to meet, with those aged between 12 and 17 able to meet with six others from six households.
Attendance at funerals, weddings and associated events will also increase to a maximum of 50 from the same date.
April 26 will also see travel restrictions across the country dropped, with people allowed to travel across the UK.
The First Minister said: “We hope that restrictions on journeys between Scotland and other parts of the UK and the wider common travel area can also be lifted, if not on April 26, then as soon as possible thereafter.”
From April 5, click-and-collect retail services, along with garden centres, car dealerships, homeware stores and barbers and hairdressers, will also be able to reopen.
The Scottish Government plans to move Scotland into Level 1 in early June, before shifting to Level 0 by the end of the month.
The First Minister said she hoped that vaccination and Test and Protect would lead Scotland closer to normality, but added she could not say when restrictions would be fully lifted.
“For me to set a precise date for all of that right now would involve plucking it out of thin air – and I’d be doing it to make my life easier, not yours,” she said.
“I am not going to do that. But I do believe that over the coming weeks – as more and more adults are vaccinated – it will be possible to set a firmer date by which many of these normal things will be possible.
“I am optimistic that this date will be over the summer.
“I know I will not be the only one now looking forward – with a real sense of hope – to hugging my family this summer.”
The First Minister said that, while she hopes to be able to lift the stay-at-home order and open retail and hospitality at different points next month, work was still required to ensure cases did not rise.
She said: “This is certainly the most hopeful I have felt about the situation for a long time.
“However, as you would expect, I do need to add a note of caution.
“I know this is the bit none of us want to hear, but the route back to normality does depend on continued suppression.”
The First Minister added: “We must continue to suppress it to the lowest level possible.”
Scotland averaged 570 new cases of coronavirus per day in the past week, Nicola Sturgeon has said.
While this figure is down from the beginning of the year, it is up from the week before.
Updating MSPs in Holyrood, the First Minister said: “The 570 cases per day on average over the past week is up slightly from an average of 490 the week before.
“This is not a massive increase, but it is clearly not the direction of travel we want to see.
“So we will be monitoring it carefully – and taking it as a reminder that we have no room for complacency.
“Care and caution in the face of this virus continues to be essential.”