How Many Days Until the Summer Solstice?

the Summer Solstice 2027 is Monday, 21 June 2027

There are 306 days between 19 August 2026 and the Summer Solstice, which falls on Monday, 21 June 2027. That is 43 weeks and 5 days, or 208 working days once Saturdays, Sundays and the US federal holidays in between are taken out — the figure that matters if you are counting delivery lead time or a work schedule rather than sleeps. The date is 2027-06-21 in ISO form and 6/21/2027 in the US format, it falls in ISO week 25 of 2027, and it is day 172 of 365.

How the date of the Summer Solstice is decided

The June solstice, the longest day in the northern hemisphere, falling on 20 or 21 June. An astronomical instant, so the calendar date depends on your time zone.

That makes it a computed date: there is no fixed day and no simple weekday rule, so it has to be worked out from a formula or a calendar of its own each year. In 2027 it works out as Monday 21 June.

the Summer Solstice is an observance rather than a federal holiday. Offices, banks and schools stay open unless an individual employer chooses otherwise, and it counts as an ordinary business day in every calculator here. Only the eleven federal holidays are treated as non-working days — the list and the reasoning are on the holiday sources page.

the Summer Solstice in the years after 2027

Both the date and the weekday move, because the rule is not tied to either.

Every convention used above — whether the start date counts, how month ends are clamped, which holidays close an office — is written out on the methodology page, including how we count the 208 working days above.