Babies cry most intensely in the evening and nighttime hours, and in most cases this is a normal part of development rather than a sign that something is wrong. Crying typically peaks around 2 months of age, when some babies cry for five hours a day or more, with the heaviest bouts clustering in the late afternoon and evening. Understanding what drives this pattern can help you figure out whether your baby’s crying falls within the expected range or signals something that needs attention.
The PURPLE Crying Period
Starting around 2 weeks of age and lasting until 3 to 5 months, nearly all babies go through a phase that pediatric researchers call the Period of PURPLE Crying. The acronym captures what makes this stage so distressing for parents: crying that Peaks in the second month, is Unexpected (starting and stopping for no clear reason), Resists soothing, comes with a Pain-like facial expression even when nothing is wrong, can be Long-lasting (several hours a day), and concentrates in the Evening.
This phase is not caused by anything you’re doing wrong. It reflects how a baby’s nervous system matures. The evening clustering likely happens because sensory stimulation builds throughout the day, and a young nervous system hasn’t yet developed the ability to regulate that input. For most babies, the intensity tapers significantly by the end of the fifth month.
Hunger and a Tiny Stomach
A one-month-old’s stomach holds only about 4 to 6 ounces. By 3 to 6 months, that capacity grows to roughly 6 to 7 ounces. That small volume means young babies digest a feeding quickly and genuinely need to eat again every two to three hours, including overnight. Night crying driven by hunger tends to follow a predictable rhythm: the baby wakes, cries, feeds eagerly, and settles back down relatively fast.
Growth spurts temporarily increase hunger beyond the usual pattern. During a spurt, your baby may demand an extra feeding or two at night for several days before settling back to their normal schedule. These spurts commonly hit around 2 to 3 weeks, 6 weeks, 3 months, and 6 months.
The Overtired Trap
It sounds counterintuitive, but a baby who has been awake too long often has a harder time falling asleep than one who is put down at the right moment. When a baby misses their sleep window, their body releases a surge of cortisol and adrenaline. Cortisol disrupts the normal sleep-wake cycle, while adrenaline triggers a fight-or-flight response. Together, these hormones can make your baby look wired, fussy, and full of frantic energy instead of drowsy.
An overtired baby may cry intensely at bedtime and then wake more frequently through the night, because those elevated stress hormones also make it harder to stay asleep once they finally drift off. Watching for early drowsiness cues (turning away from stimulation, rubbing eyes, yawning) and starting your wind-down routine before those cues escalate can help you catch the window before the stress hormones kick in.
Reflux That Gets Worse Lying Down
If your baby seems fine when upright but cries, arches, or sounds hoarse after being laid flat, reflux could be the issue. The valve between a baby’s stomach and esophagus is still immature, and stomach contents can push past it when the baby shifts from an upright to a lying-down position. Some babies spit up visibly. Others have what’s called silent reflux, where stomach acid rises into the esophagus but gets swallowed back down before it reaches the mouth. These babies may cough, sound raspy, or seem uncomfortable without any obvious spit-up.
Reflux-related crying tends to be worst shortly after a feeding, especially once the baby is placed on their back. Keeping your baby upright for 20 to 30 minutes after feeding can reduce episodes. Most babies outgrow reflux as their digestive system matures, typically between 12 and 18 months.
Room Temperature and Physical Discomfort
Babies are sensitive to temperature but can’t tell you they’re too hot or too cold. The recommended room temperature for a sleeping infant is 16 to 20°C (about 61 to 68°F). Keeping the room in this range also helps lower the risk of SIDS. A baby’s hands and feet will normally feel cooler than the rest of their body, so checking those spots can be misleading. Instead, feel the skin on your baby’s chest or the back of their neck. If it feels hot or sweaty, remove a layer of clothing or bedding.
Other physical irritants are easy to overlook: a hair or thread wrapped tightly around a finger or toe (called a hair tourniquet), a scratchy clothing tag, a wet diaper that’s been on too long, or simply being swaddled too tightly. A quick head-to-toe check when nighttime crying doesn’t fit the usual pattern can sometimes reveal a straightforward fix.
Sleep Regressions at Predictable Ages
Just when you think you’ve cracked the code, a baby who was sleeping well can suddenly start waking and crying multiple times a night. These sleep regressions tend to cluster around developmental leaps. The most well-known one hits around 4 months, when a baby’s sleep architecture shifts from newborn-style sleep to a more adult-like cycle with distinct stages. This reorganization means the baby now partially wakes between sleep cycles and may struggle to fall back asleep independently.
Around 9 months, separation anxiety becomes a major factor. Your baby now understands that you exist even when you leave the room, but doesn’t yet grasp that you’ll come back. Waking at night and realizing you’re not there can trigger intense crying. Teething pain is another common disruptor that can surface at any point, typically starting between 4 and 7 months. A regression usually resolves within two to four weeks as the baby adjusts to the new skill or developmental stage.
Colic: When Crying Exceeds the Norm
If your baby cries for more than three hours a day, more than three days a week, for longer than three weeks, pediatricians classify this as colic. Despite decades of research, there’s no single confirmed cause. Colic is considered a benign condition, meaning it doesn’t harm the baby, but it’s genuinely exhausting for parents. It follows the same general timeline as the PURPLE crying period, peaking around 6 to 8 weeks and resolving by 3 to 4 months.
There’s no reliable cure for colic. What helps varies from baby to baby: rhythmic motion, white noise, skin-to-skin contact, or a car ride may calm one baby and do nothing for another. The most important thing to know is that colicky crying is not a reflection of your parenting, and it will end.
Signs That Need Medical Attention
Most nighttime crying is developmentally normal, but certain symptoms alongside crying signal something more serious. A baby under 3 months with a fever needs emergency care. Other red flags include a bulging soft spot on the top of the head, a rash that doesn’t fade when you press on it, pale or blotchy skin (especially around the lips), fast or labored breathing, and extreme drowsiness where the baby is difficult to wake.
Watch for signs of dehydration too: fewer than half the usual number of wet diapers, refusal to drink, or repeated vomiting. If your baby has been crying nonstop and you notice any of these signs, or if the crying sounds different from their usual fussing (higher pitched, weaker, or more urgent), seek medical evaluation promptly. Trust your instincts. You know your baby’s normal sounds better than anyone, and a shift in the quality of crying is worth taking seriously.