Never miss an important date
How Many Days Until First Day of Summer 2027?
401 days left.
First Day of Summer is on Monday, June 21, 2027.
Get the free iPhone app with countdown widgets, reminder alerts, and easy sharing so you can plan ahead for any event.
401
days
First Day of Summer
Outside
Free iPhone app with home screen widgets. Used by 300k+ people.
There are 401 days until First Day of Summer 2027, which falls on Monday, June 21, 2027. That is 57 weeks and 2 days away, or roughly 13 months. First Day of Summer is an astronomical season that begins at a solstice or equinox, the precise moment Earth's tilt reaches a turning point. Because First Day of Summer falls on a Monday, it joins the Saturday and Sunday before it to create a natural three-day weekend.
Counting down turns a vague "soon" into a clear number of days you can plan around — booking travel, sending cards, or simply building anticipation. Many people begin preparing for a date like this two to three months ahead, and a visible countdown helps pace that preparation rather than leaving everything to the final week. If you are counting down to First Day of Summer, you can add a free Outside countdown widget to your iPhone home screen; it updates every day and can be shared with friends and family.
Looking for First Day of Summer 2026?
Track First Day of Summer from your home screen
Home Screen Widgets
Beautiful countdown widgets that sit right on your home screen.
Lock Screen Widgets
See your countdown without even unlocking your phone.
Live Activities
Real-time countdown updates on your Dynamic Island.
The Science Behind First Day of Summer
Seasons are driven by the tilt of Earth's axis — roughly 23.5 degrees — not by how close the planet is to the Sun. As Earth orbits, each hemisphere leans toward or away from the Sun, changing the angle of sunlight and the length of the day. The astronomical start of a season is pinned to a solstice or an equinox, the precise moment that geometry reaches a turning point.
That is why the start of First Day of Summer 2027 lands on a specific date and even a specific time, rather than the first of a month. Equinoxes bring near-equal day and night worldwide; solstices mark the longest or shortest day of the year. Knowing the exact changeover is useful for gardeners, photographers, and anyone tracking daylight hours.
Frequently Asked Questions
How many days until First Day of Summer?
There are 401 days until First Day of Summer 2027, which falls on Monday, June 21, 2027. That's 57 weeks, or roughly 14 months, from today.
When is First Day of Summer 2027?
First Day of Summer 2027 is on Monday, June 21, 2027 — 401 days from today. Add it to your calendar or set up a free countdown widget on your iPhone home screen with the Outside app.
What causes First Day of Summer to begin?
First Day of Summer begins because of the 23.5-degree tilt of Earth's axis. As the planet orbits the Sun, each hemisphere leans toward or away from it, changing sunlight and day length. The season's astronomical start is pinned to a solstice or equinox.
Is there a free First Day of Summer countdown app?
Yes. Outside is a free iPhone app with a First Day of Summer countdown widget for your home screen. It includes reminder alerts, calendar sync, and shared countdowns. Used by 300k+ people.
How long until First Day of Summer?
First Day of Summer 2027 is 57 weeks and 2 days away — roughly 14 months from now. Set a reminder so the day doesn't slip past you.
