At 16 months, waking up crying is extremely common and usually traces back to one of a handful of causes: teething pain, separation anxiety, a nap schedule that needs adjusting, or the massive cognitive leaps happening in your toddler’s brain. Most of these resolve on their own within a few weeks, but knowing which one you’re dealing with helps you respond in the right way.
Teething Pain Peaks at This Age
Sixteen months falls right in the window when first molars push through the gums. These are the largest teeth your toddler has cut so far, and the process is significantly more uncomfortable than the front teeth that came in earlier. Upper first molars typically emerge between 13 and 19 months, lower first molars between 14 and 18 months, and canines (the pointed teeth beside the front four) start arriving around 16 to 22 months on top. Your child could be dealing with multiple teeth at once.
Teething pain tends to feel worse at night because there are fewer distractions. A toddler who seems fine during the day may wake up crying when the discomfort is the only thing they can focus on. Common daytime clues include biting or chewing on objects, irritability, drooling, and loss of appetite. If you notice any of these alongside the nighttime waking, molars are a likely culprit. The worst of it usually passes within a few days per tooth, though the overall molar phase can stretch across several weeks.
Separation Anxiety Is at Its Strongest
Separation anxiety in babies peaks between 9 and 18 months, which puts your 16-month-old right in the thick of it. This isn’t a behavioral problem. It’s actually a sign of healthy attachment. Your toddler has formed a strong bond with you and genuinely misses you when you’re not there. At this age, children are naturally self-focused and worry that their needs won’t be met if their usual caregiver isn’t around.
What this looks like at night: your toddler wakes between sleep cycles (which happens naturally every 60 to 90 minutes), realizes they’re alone, and cries because they want you back. The crying often stops quickly once you appear. If your child calms down almost immediately when you enter the room, separation anxiety is probably the main driver. This phase fades over time as your toddler develops a more secure understanding that you always come back.
The Nap Transition Can Wreck Nighttime Sleep
Around 16 months, many toddlers start shifting from two naps to one. This transition is messy, and it directly affects how they sleep at night. If your toddler is getting too much daytime sleep, they may not have enough sleep pressure built up to stay asleep overnight, leading to long middle-of-the-night wakings (sometimes called “split nights”). If they’re getting too little daytime sleep, they become overtired, which paradoxically makes nighttime sleep worse, not better. Overtired toddlers produce more stress hormones, making it harder for them to settle and stay asleep.
Signs that the nap transition is behind the crying include: resisting one or both naps, taking very short naps, consistently sleeping less than 10 hours at night, or waking for long stretches in the middle of the night. Toddlers between 1 and 2 need 11 to 14 total hours of sleep per day including naps. If your child’s schedule doesn’t add up to something in that range, adjusting nap timing or length is worth trying. On days when only one nap happens and your toddler is clearly overtired by evening, moving bedtime earlier can prevent the frustrated, tearful wind-down that often follows.
New Skills Keep Their Brain Buzzing
Sleep regressions at this age are closely tied to developmental leaps. At 16 months, toddlers are refining their walking, starting to climb, building a vocabulary, and learning to use objects as tools. These skills don’t shut off at bedtime. The same neural activity that helps your child practice walking during the day can activate during lighter sleep stages, pulling them toward wakefulness. Some toddlers even stand up in the crib while still half-asleep, then cry because they’re disoriented or can’t figure out how to lie back down.
Language development plays a role too. Toddlers at this age are beginning to understand far more words than they can say, and the frustration of not being able to communicate what they need (a drink, a lost pacifier, comfort) often comes out as crying. Developmental sleep regressions typically last two to six weeks, then resolve as the new skills become routine.
Ear Infections and Illness
If the crying is sudden, more intense than usual, or accompanied by a fever, an ear infection is worth considering. Ear infections are one of the most common childhood illnesses, and they hurt more when a child is lying down because the pressure in the middle ear shifts. A toddler who can’t yet say “my ear hurts” will show it in other ways: tugging or pulling at their ears, unusual fussiness, fluid draining from the ear, balance problems, or not responding to quiet sounds the way they normally would.
Other illnesses that spike at night include colds (congestion worsens when lying flat) and stomach bugs. The key distinction between illness and the other causes on this list is that illness tends to come on abruptly rather than building over days or weeks, and your child will usually seem off during the day too.
Night Terrors vs. Nightmares
Parents often wonder if their toddler is having nightmares, but true nightmares are uncommon at 16 months. Nightmares happen during dream-heavy sleep later in the night and cause a child to wake up frightened but aware. Night terrors, where a child screams, thrashes, and appears terrified while still technically asleep, are also unlikely at this age. They’re most common between ages 3 and 8. During a night terror, a child’s eyes may be open, but they won’t recognize you and won’t remember the episode afterward.
If your 16-month-old is crying in the early part of the night with eyes open but seems unresponsive to comfort, it could be an early night terror, but this is rare. Most nighttime crying at this age is better explained by the causes above.
How to Tell Which Cause You’re Dealing With
Pay attention to the timing and pattern. Crying that happens within the first few hours of bedtime and involves thrashing or seeming “out of it” points toward a partial arousal or overtiredness. Crying in the second half of the night is more consistent with pain, hunger, or separation anxiety. Crying that coincides with your toddler learning a major new skill, like climbing or adding several new words, suggests a developmental regression.
If your child calms quickly with your presence, separation anxiety is the most likely explanation. If they remain upset even while you hold them, pain from teething or illness is more probable. And if the waking happens at the same time every night for weeks, look at the nap schedule first, because that pattern often reflects a structural sleep issue rather than a temporary disruption.
Most causes of nighttime crying at 16 months overlap and reinforce each other. A toddler cutting molars who is also in the middle of a nap transition and experiencing separation anxiety is going to have a rough few weeks. The good news is that all of these are temporary phases, and most families see improvement within two to four weeks without any major intervention.