Seasonal Constellations

The constellations that are visible in the night sky in the evening change from season to season because stars appear to move by 90 degrees across the sky every three months. Even though some constellations are circumpolar to northern or southern latitudes and can be seen year round, the sky offers different sights from different locations at different times of year.

The stars appear to move about 15 degrees per hour on average, completing a full circle (360 degrees) every 24 hours. Some rise directly east and set directly west, taking longer to cross the sky, but most of them follow shorter arcs, staying closer to the horizon before setting. As they move across the sky, the stars stay in the same patterns. These patterns, which we know as constellations, may appear larger or smaller at different times of the night or sideways or upside down at different times of year, but their shape never changes, at least not in our lifetime.

Summer and winter constellations are different because stars in fact take a little less than an hour to move by 15 degrees, and they complete an entire circle in 23 hours and 56 minutes. In other words, they rise and set four minutes earlier each night. The distance they cross in those remaining 4 minutes is a little less than 1 degree, which means that they move about 361 degrees per day. These extra degrees eventually add up and, as a result, the stars rise and set an hour earlier every two weeks, two hours earlier each month and, after a full year, we see them in the same position as before. As the seasons pass, different constellations of stars are visible in different areas of the sky because the stars move by about 90 degrees from one season to the next.

constellations by season

Seasonal constellations – illustration (modified) from 1911 Encyclopædia Britannica

The term “seasonal constellations” usually refers to the constellations that are visible in the sky at around 9 pm in the evening or to constellations that are best observed during a particular season. These, however, are not the only constellations that can be seen in the sky on any given evening. For instance, Andromeda, a prominent autumn constellation, can be seen high overhead on summer evenings around midnight. Orion, which dominates the winter sky in the evening, can also be seen in the late summer, when it rises just before dawn. The list of seasonal constellations is provided below.

Northern spring/southern autumn constellations (late March to late June):

Antlia Corvus Lynx
Boötes Crater Musca
Cancer Crux Pyxis
Canes Venatici Hydra Sextans
Centaurus Leo Ursa Major
Chamaeleon Leo Minor Ursa Minor
Coma Berenices Lupus Virgo

Northern summer/southern winter constellations (late June to late September):

Apus Draco Pavo
Aquila Equuleus Sagitta
Ara Hercules Sagittarius
Capricornus Indus Scorpius
Circinus Libra Scutum
Corona Australis Lyra Serpens
Corona Borealis Microscopium Telescopium
Cygnus Norma Triangulum Australe
Delphinus Ophiuchus Vulpecula

Northern autumn/southern spring constellations (late September to late December):

Andromeda Grus Pisces
Aquarius Lacerta Piscis Austrinus
Aries Octans Sculptor
Cassiopeia Pegasus Triangulum
Cepheus Perseus Tucana
Cetus Phoenix

Northern winter/southern summer constellations (late December to late March):

Auriga Eridanus Orion
Caelum Fornax Pictor
Camelopardalis Gemini Puppis
Canis Major Horologium Reticulum
Canis Minor Hydrus Taurus
Carina Lepus Vela
Columba Mensa Volans
Dorado Monoceros

Not all constellations are visible from every location on Earth. The southern constellations Crux, Carina and Centaurus, for instance, are circumpolar to observers in the southern hemisphere, but are invisible to most, if not all, northern observers. Similarly, the northern constellations Ursa Major, Ursa Minor, Cassiopeia, Cepheus and Draco are visible in the northern hemisphere throughout the year, but cannot be seen from most locations south of the equator. Nevertheless, there is a best time of year to observe each of the constellations, even the least conspicuous ones. The table below shows the best months to observe the constellations in the evening (9 pm) and the latitudes (northern and southern) between which they are visible.

Constellation Month Northern latitude Southern latitude
Andromeda November 90° 40°
Antlia April 45° 90°
Apus July 90°
Aquarius October 65° 90°
Aquila August 90° 75°
Ara July 25° 90°
Aries December 90° 60°
Auriga February 90° 40°
Boötes June 90° 50°
Caelum January 40° 90°
Camelopardalis February 90° 10°
Cancer March 90° 60°
Canes Venatici May 90° 40°
Canis Major February 60° 90°
Canis Minor March 90° 75°
Capricornus September 60° 90°
Carina March 20° 90°
Cassiopeia November 90° 20°
Centaurus May 25° 90°
Cepheus November 90° 10°
Cetus November 70° 90°
Chamaeleon April 90°
Circinus July 30° 90°
Columba February 45° 90°
Coma Berenices May 90° 70°
Corona Australis August 40° 90°
Corona Borealis July 90° 50°
Corvus May 60° 90°
Crater April 65° 90°
Crux May 20° 90°
Cygnus September 90° 40°
Delphinus September 90° 70°
Dorado January 20° 90°
Draco July 90° 15°
Equuleus September 90° 80°
Eridanus December 32° 90°
Fornax December 50° 90°
Gemini February 90° 60°
Grus October 34° 90°
Hercules July 90° 50°
Horologium December 30° 90°
Hydra April 54° 83°
Hydrus November 90°
Indus September 15° 90°
Lacerta October 90° 40°
Leo April 90° 65°
Leo Minor April 90° 45°
Lepus January 63° 90°
Libra June 65° 90°
Lupus June 35° 90°
Lynx March 90° 55°
Lyra August 90° 40°
Mensa January 90°
Microscopium September 45° 90°
Monoceros February 75° 90°
Musca May 10° 90°
Norma July 30° 90°
Octans October 90°
Ophiuchus July 80° 80°
Orion January 85° 75°
Pavo August 30° 90°
Pegasus October 90° 60°
Perseus December 90° 35°
Phoenix November 32° 90°
Pictor January 26° 90°
Pisces November 90° 65°
Piscis Austrinus October 55° 90°
Puppis February 40° 90°
Pyxis March 50° 90°
Reticulum January 23° 90°
Sagitta August 90° 70°
Sagittarius August 55° 90°
Scorpius July 40° 90°
Sculptor November 50° 90°
Scutum August 80° 90°
Serpens July 80° 80°
Sextans April 80° 90°
Taurus January 90° 65°
Telescopium August 40° 90°
Triangulum December 90° 60°
Triangulum Australe July 25° 90°
Tucana November 25° 90°
Ursa Major April 90° 30°
Ursa Minor June 90° 10°
Vela March 30° 90°
Virgo May 80° 80°
Volans March 15° 90°
Vulpecula September 90° 55°