The summer of 2026 officially begins this Sunday, June 21. In mainland Spain and the Balearic Islands, the astronomical start of the season occurs at 10:24 AM, according to calculations by the National Astronomical Observatory, which is part of the National Geographic Institute.
In the Canary Islands, it will be one hour earlier: at 9:24 AM. The difference is not due to the solstice occurring earlier there, but to the time zone. The solstice is a unique astronomical moment for the entire planet: in 2026 it occurs at 08:24 UTC.
That moment marks the beginning of astronomical summer in the Northern Hemisphere and astronomical winter in the Southern Hemisphere.
What time does summer start in Spain
- In Spain, the summer of 2026 begins on Sunday, June 21 at 10:24 AM in the Peninsula and the Balearic Islands.
- In the Canary Islands, the start will be at 9:24 AM.
The season will last approximately 93 days and 16 hours, until September 23, when astronomical autumn will begin.
Summer solstice time in Europe
The solstice occurs at the same instant throughout Europe, but each country sees it at its local time.
- In mainland Spain, France, Italy, Germany, Belgium, and much of Central Europe, it will be at 10:24 AM.
- In the Canary Islands, mainland Portugal, the United Kingdom, and Ireland, it will be at 9:24 AM.
- In Greece, Finland, Romania, and other Eastern European countries, it will be at 11:24 AM.
The key is to remember that the base figure is 08:24 UTC. From there, each country adds its time zone difference.
Summer solstice time in the United States
In the United States, the astronomical summer of 2026 also begins on Sunday, June 21, but in the early morning.
- On the East Coast, cities like New York, Washington, or Miami will experience the solstice at 4:24 AM.
- In the central zone, such as Chicago or Dallas, it will be at 3:24 AM.
- In the mountain zone, such as Denver, it will be at 2:24 AM.
- On the West Coast, cities like Los Angeles, San Francisco, or Seattle will have the start of summer at 1:24 AM.
- In Hawaii, due to the time difference, the solstice will still fall on Saturday, June 20, in the evening.
What exactly is the summer solstice
The summer solstice is not an entire day, but a precise moment. It is the moment when the Northern Hemisphere reaches its maximum inclination towards the Sun.
The Earth revolves around the Sun with its axis tilted about 23.5 degrees. That tilt is the cause of the seasons. When the Northern Hemisphere is more oriented towards the Sun, it receives more hours of daylight and solar radiation arrives more directly.
That is why the June solstice marks the day with the most hours of daylight of the year in the Northern Hemisphere.
Why it is the longest day of the year
June 21st is the longest day of the year in the Northern Hemisphere because the Sun reaches its highest apparent position in the sky and remains above the horizon for longer.
The further north a place is, the greater the difference in daylight compared to winter. That is why the solstice day is longer in Bilbao than in Seville, and much longer in Stockholm than in Madrid.
Within the Arctic Circle, the so-called midnight sun even occurs: the Sun does not set during the night.
Does summer always start on June 21st?
Not always. Astronomical summer in the Northern Hemisphere can begin on June 20th, 21st, or, more rarely, the 22nd, depending on the year and the time zone.
The reason is that it does not take the Earth exactly 365 days to complete its orbit around the Sun, but slightly longer. That is why leap years exist and why solstices and equinoxes do not always fall at the same time.
In 2026, summer begins on June 21st.
Astronomical summer and meteorological summer: they are not the same
Astronomical summer begins with the solstice, but meteorological summer began on June 1st.
The difference is simple. Astronomical seasons depend on the Earth's position relative to the Sun. Meteorological seasons are organized by full months to facilitate climate analysis: meteorological summer is June, July, and August.
That is why it can be hot before the solstice and why a heatwave can start before astronomical summer officially arrives.
Why the longest day is not usually the hottest
Although the solstice is the day with the most daylight, it is not usually the hottest day of the year. The reason is thermal lag.
The atmosphere, oceans, and land surface take time to heat up. After the solstice, the days begin to shorten slowly, but the Northern Hemisphere continues to accumulate heat for several weeks.
That is why, in Spain, the hottest days usually occur in July or August, not necessarily on June 21st.
Does it have anything to do with San Juan?
No. Saint John's Night, from June 23 to 24, is a cultural and popular celebration linked to the beginning of summer, but it does not mark the astronomical start of the season.
In 2026, summer will have already begun: on Sunday, June 21 at 10:24 AM in peninsular Spain.
Saint John's Night is very close to the solstice, and that is why it has historically been associated with light, fire, and rituals for the change of season, but it does not coincide exactly with the astronomical moment.