Cicadas are overwhelmingly daytime insects. Their defining behavior, the deafening chorus that blankets neighborhoods and forests, is a daytime affair driven by warmth and light. Field recordings of tropical cicada species show chorusing beginning around sunrise and continuing throughout the day, and the pattern holds across most of the roughly 3,000 known species worldwide.1PeerJ. The circadian calling activity of a lebinthine cricket with high-frequency calls is unaffected by cicada choruses in the day That said, cicadas are not entirely absent from the nighttime world, and certain circumstances push their activity into hours you would not expect.
Peak Activity Runs from Mid-Morning Through Late Afternoon
If you live anywhere with a healthy cicada population, your ears already know the rough schedule. The chorus typically builds in the morning hours and intensifies as the day warms. Field recordings of cicada species in Southeast Asian forests documented choruses beginning on average around 6:52 a.m., with individual species starting as early as 6:34 a.m. The calling continued essentially all day, with overlapping individuals producing near-continuous sound.1PeerJ. The circadian calling activity of a lebinthine cricket with high-frequency calls is unaffected by cicada choruses in the day In Florida, cicadas are best known for their loud calls heard during the day, usually from trees.2EDIS / University of Florida. Cicadas (of Florida), Neocicada hieroglyphica (Say), Tibicen, Diceroprocta and Melampsalta spp. (Insecta: Hemiptera: Cicadidae)
The timing shifts somewhat depending on species and geography. In temperate North America, the midday and early afternoon hours tend to be the loudest. Some species, like those in the genus Neotibicen (formerly Tibicen), are well known for singing during the hottest part of the day. Others start earlier in the morning or sing into dusk. A few species are specifically crepuscular, calling primarily at dawn or twilight. But the broad pattern is consistent: cicadas are loudest and most active when it is warm and bright.
Temperature Is the Real Clock
The reason cicadas cling to daytime hours has less to do with light than with heat. Singing is one of the most physically demanding things a cicada does, and the mechanism that produces sound requires elevated body temperature to function properly. Cicadas sing by rapidly buckling a pair of stiff membranes called tymbals on the sides of their abdomen. The muscles driving these tymbals need to be warm to contract fast enough to produce the characteristic buzzing or pulsing song.
Research on the North American species Tibicen winnemanna found that the timbal muscles operate in a temperature range well above ambient air. During a “warm-up” buzz, muscle temperature sat around 28 to 30°C, but full calling song required muscle temperatures between about 36 and 40°C. That means the muscle needed to be roughly 13°C warmer than the surrounding air to produce a proper call.3PubMed. Timbal muscle physiology in the endothermic cicada Tibicen winnemanna (Homoptera: Cicadidae) As temperature climbed, the muscles contracted faster and produced more tension, while the time it took for each contraction shortened. In practical terms, a cicada sitting in cool morning shade literally cannot sing its full song. It needs to warm up first, either by basking in sunlight or by generating heat internally through preflight muscle vibrations.
This thermal requirement explains why the chorus tends to peak in the warmest part of the day and why cooler, overcast days sometimes silence cicadas entirely. It also explains why different species call at different times. Species that are better at generating their own internal heat can sing at lower ambient temperatures and therefore start earlier in the morning or continue later into the evening. Species that rely more on solar basking are restricted to the sunniest, hottest windows. Either way, nighttime temperatures in most habitats simply fall too low to sustain singing.
When Cicadas Sing at Night
Despite their strong daytime preference, cicadas do sometimes call after dark, and the phenomenon has become more common in urban areas. A study using autonomous recording units in Japanese cities found that two species, Platypleura kaempferi and Graptopsaltria nigrofuscata, extended their calling into nighttime hours at urban sites. The researchers attributed this to artificial illumination and elevated nighttime temperatures caused by the urban heat island effect.4Ecological Research. Using Autonomous Recording Units to Detect Variation in Cicada Calling Pattern Across Urbanized and Green Spaces
This makes sense given the thermal physiology involved. Cities retain more heat after sunset than surrounding rural or forested areas, sometimes keeping nighttime temperatures several degrees warmer. If the air stays warm enough, the thermal barrier to singing disappears, and the cicadas keep going. Bright streetlights and illuminated buildings may compound the effect by tricking the insects’ light-sensitive behavioral cues into registering “daytime” conditions well after sunset.
If you have ever heard cicadas screaming at 11 p.m. in a hot city, you were not imagining things. But this is an artifact of the artificial environment, not the insect’s natural schedule. In forests and rural areas under the same latitude and climate, those same species typically fall silent after dusk.
Nymph Emergence Is the One Truly Nocturnal Event
There is one stage of a cicada’s life that is genuinely nocturnal, and it is the most dramatic moment of the entire life cycle. When cicada nymphs are ready to shed their underground existence and become winged adults, they dig out of the soil and climb the nearest vertical surface, almost always after dark. If you have ever found rows of empty cicada shells clinging to tree trunks, those shells were left there overnight.
The timing is strategic. A freshly molted cicada is soft, pale, and completely defenseless. Its wings are crumpled and wet, and it takes hours for the exoskeleton to harden. Emerging at night reduces exposure to visual predators like birds that would easily pick off a slow, conspicuous, soft-bodied insect sitting motionless on a tree trunk. By the time morning arrives, the new adult has hardened enough to fly.
Mass emergence events, like those of the periodical cicadas (Magicicada) in eastern North America, unfold primarily after sunset on warm, humid evenings. The trigger for when nymphs decide to dig out involves soil temperature reaching a threshold, generally around 18°C (64°F) at a depth of about 20 cm. Rainfall also plays a role. Research on urban periodical cicada emergence found that precipitation two to three weeks before emergence significantly increased emergence counts, while rain in the week immediately prior had no effect.5PubMed Central. Rainfall Timing as a Key Driver of Cicada Peak Emergence in Urban Habitats The rain likely softens the soil weeks in advance, making it easier for nymphs to tunnel upward when the time comes.
What Cicadas Do During the Night
Outside of the emergence window, adult cicadas are relatively inactive at night. They roost on branches and trunks, staying still to avoid attracting nocturnal predators. Their grip on bark is strong enough to keep them in place, and their cryptic coloring, often browns, greens, and grays that match tree bark, helps them blend in. You can sometimes find resting cicadas with a flashlight, sitting motionless on a tree where they were singing loudly a few hours earlier.
Cicadas are also attracted to artificial lights at night, which is a well-known behavior anyone living near a porch light during cicada season has observed. This is not purposeful activity so much as a side effect of their visual system. Cicada compound eyes are large and well developed, with roughly 7,500 individual facet lenses per eye and broad visual fields, including significant binocular overlap in the frontal and dorsal regions.6PubMed Central. The visual system of the Australian ‘Redeye’ cicada (Psaltoda moerens) These eyes are built for daytime use, where detecting predators and navigating between trees matter. At night, bright artificial lights overwhelm the visual system and draw cicadas in, the same way moths famously spiral around bulbs. The result is clumsy cicadas crashing into windows and buzzing frantically under streetlights, which can give the mistaken impression that they are actively nocturnal.
How Cicadas Keep Their Internal Clock
Like most insects, cicadas have an internal circadian clock that regulates their daily rhythms. Researchers have identified a circadian neuropeptide called pigment-dispersing factor (PDF) in the brains of cicadas. A study on the last-summer cicada Meimuna opalifera in Japan cloned the gene encoding PDF from adult cicada brains and found that its amino acid sequence was nearly identical to the same clock-related peptide found in crickets and other insects.7BioOne (Zoological Science). A Circadian Neuropeptide, Pigment-Dispersing Factor–PDF, in the Last-Summer Cicada Meimuna opalifera: cDNA Cloning and Immunocytochemistry
PDF is involved in synchronizing daily behavioral rhythms across many insect groups. Its presence in cicada brains suggests that the timing of singing is not simply a response to ambient temperature but is also regulated by an internal clock that anticipates the daily cycle. This would explain why cicadas in controlled lab conditions still tend to show rhythmic activity patterns even when temperature and light are held constant. The clock and the temperature constraint likely work together: the internal rhythm primes the insect to be ready to sing during daytime hours, while actual thermal conditions determine how intensely and how long singing occurs on any given day.
Why People Confuse Cicadas with Nocturnal Insects
One of the most common sources of confusion is mistaking cicadas for crickets and katydids. If you hear a loud insect chorus at night, especially a continuous droning or chirping sound, it is almost certainly crickets, katydids, or tree frogs, not cicadas. Crickets and katydids are genuinely nocturnal singers. They fill the acoustic space that cicadas vacate at dusk, and in many habitats the two groups neatly divide the 24-hour soundscape between them. Cicadas dominate the daytime; crickets and katydids own the night.
The confusion runs deep enough that many people use “cicada” as a generic term for any loud insect, leading them to attribute nighttime sounds to cicadas when they are hearing something else entirely. The two groups are not closely related. Cicadas are in the order Hemiptera (true bugs) and produce sound using those specialized tymbals. Crickets and katydids are in the order Orthoptera and produce sound by rubbing their wings together. The mechanisms are completely different, and so are the schedules.
Another source of confusion is the periodical cicada emergence itself. Because nymphs emerge at night and newly molted adults may still be clinging to trees and calling weakly at dawn, people sometimes describe the entire event as “nocturnal.” The emergence is nocturnal. The adult life that follows, including the weeks of ear-splitting chorus, is thoroughly diurnal.
Seasonal Timing and When to Expect Cicadas
Beyond their daily schedule, cicadas follow seasonal patterns that vary widely by species. In North America, annual cicadas (sometimes called “dog-day cicadas” because they appear during the hottest stretch of summer) begin emerging in late June or July and sing through August or September. Periodical cicadas, by contrast, emerge in late April through June, depending on latitude and soil temperature. Tropical species may call year-round, since temperatures rarely drop below the threshold for singing.
Soil temperature is the primary seasonal trigger for emergence. Nymphs spend years underground, feeding on root fluids, and they begin their final ascent when the soil warms past a species-specific threshold. Rainfall timing matters as well: the finding that precipitation two to three weeks before emergence drives higher emergence counts, while immediate rainfall does not, suggests that nymphs are responding to soil conditions shaped by weather patterns over a multi-week window, not to a single rainstorm the night they dig out.5PubMed Central. Rainfall Timing as a Key Driver of Cicada Peak Emergence in Urban Habitats
Climate change is likely shifting these seasonal windows. Warmer springs mean soil thresholds are reached earlier, and some entomologists have reported periodical cicada emergences arriving weeks ahead of historical records. Urban areas, which warm faster due to impervious surfaces and heat retention, tend to see earlier emergences than surrounding forests. For anyone trying to predict when cicadas will appear in their area, soil temperature at about 20 cm depth is a better guide than the calendar date.
Cicadas and Their Predators
The daytime activity pattern exposes cicadas to a specific set of predators. Birds are the most significant, and many species time their breeding season to overlap with cicada emergences. Mammals also eat cicadas opportunistically. A global review found that cicadas serve as food for a wide range of mammalian predators and that changes in cicada availability and timing could have broader effects on predator behavior and populations.8Wildlife Biology. Cicada as a food for mammals: a global review and implications for mammal behaviour and populations Squirrels, raccoons, foxes, and even bears have been documented eating cicadas during mass emergences.
Periodical cicadas counter predation not by hiding or being active at safe hours but through sheer numbers. The strategy is called predator satiation: so many individuals emerge simultaneously that predators physically cannot eat them all, and enough survive to reproduce. This only works because the emergence is synchronized, which brings us back to timing. The nymphs emerge together at night, the adults harden together by morning, and the chorus begins in unison during the day. The whole system depends on precise timing at every scale, from the circadian to the seasonal to the multi-year cycle.
Nocturnal predators like owls and bats do take cicadas, but mostly during the vulnerable emergence window or when adults blunder into lights at night. During normal daytime activity, cicadas rely on flight speed, erratic movement, and their startling buzz to escape birds and other visual hunters. A cicada sitting quietly on a branch at night is safer than one might expect, because few nocturnal predators specifically search bark for roosting insects when easier prey is available on the ground or in the air.
Do Any Cicadas Sing Exclusively at Night
A handful of species worldwide are known to call primarily at dusk or into the early nighttime hours, but truly nocturnal cicada species are rare and poorly studied. Some Southeast Asian and Australian species have been recorded calling at twilight or just after dark, particularly in dense tropical forests where the canopy blocks light and keeps temperatures more stable. These species tend to be smaller and quieter than the classic daytime chorus singers, which may be why they are less familiar.
The scarcity of nocturnal cicada species likely reflects the thermal constraint. In most environments, nighttime temperatures simply do not support the high muscle temperatures needed for sustained singing. The exceptions tend to occur in consistently warm tropical lowlands where nighttime temperatures remain above 25°C or so, a threshold warm enough for at least some species to power their tymbals without solar basking. Even in these cases, the singing tends to be concentrated at dusk rather than deep into the night, suggesting that circadian rhythms and predator avoidance both play a role in keeping activity to a narrow twilight window rather than extending it through the full dark period.