Scars can genuinely become more painful or sensitive when the weather changes, and rain is one of the most commonly reported triggers. The phenomenon has real biological plausibility: drops in barometric pressure, shifts in temperature, and changes in humidity all interact with the structurally abnormal tissue that makes up a scar. That said, the science is messier than the folk wisdom suggests, with psychology amplifying what physiology starts.
What Happens in the Atmosphere Before Rain
When a rainstorm approaches, barometric pressure typically drops. This is the detail that gets the most attention in weather-pain research, because it could plausibly affect tissue. Under normal conditions, the atmosphere presses inward on your body with a relatively stable force. When that external pressure decreases, tissues have slightly less force keeping them compressed. In healthy skin, this shift is trivial. But in tissue that’s already damaged, stiff, or laced with sensitized nerve endings, even a small mechanical change can register as discomfort.
A 2025 study in mice with nerve-injury pain tested this directly. Animals were exposed to a series of three consecutive drops in barometric pressure, mimicking what happens as a weather front moves in. After those pressure drops, the mice showed significantly more pain responses to light touch on their injured paws than they did before the pressure changed. When barometric pressure was held steady, there was no such increase. The pressure drops also sent stress hormone levels soaring: mice exposed to the drops had nearly three times the plasma corticosterone of those left at stable pressure.1PubMed Central. The effects of lowering barometric pressure on pain behavior and the stress hormone in mice with neuropathic pain
That’s an animal model, not a clinical trial in humans, and it specifically studied nerve-injury pain rather than scar pain. But it provides one of the cleanest demonstrations that dropping barometric pressure alone, with temperature and humidity held constant, is enough to amplify pain behavior in already-sensitized tissue.
Why Scar Tissue Reacts Differently Than Normal Skin
A scar is not just a cosmetic mark. It’s a fundamentally different type of tissue compared to the skin it replaced, and those structural differences are the reason weather changes can bother it.
Normal skin has collagen fibers arranged in a somewhat random, basket-weave pattern. This disorganized structure is actually a feature: it lets skin stretch, compress, and bounce back. Scar tissue, by contrast, has collagen fibers aligned much more in parallel, with tighter bundle packing. One study measuring this directly found that scar tissue had a collagen orientation index of 0.44 compared to 0.26 in normal skin, and its collagen bundles were packed more tightly.2PubMed. Collagen morphology in human skin and scar tissue: no adaptations in response to mechanical loading at joints Think of it as the difference between a loosely knitted sweater that moves with you and a tightly woven canvas that resists bending.
On top of the collagen problem, scars tend to lack the elastic fibers that give normal skin its snap-back quality. The protein elastin is either absent or poorly formed in scar tissue, leaving it inflexible and inelastic compared to the surrounding dermis.3PubMed. Elastin and collagen fibres in cutaneous wound healing When barometric pressure drops and tissues swell slightly, normal skin can accommodate the change. Stiff, inelastic scar tissue cannot stretch as readily, so even a minor expansion puts mechanical stress on the structures within and around it.
This matters because scar tissue often contains more nerve fibers than you’d expect. Research in animal models has shown that mechanical tension during healing promotes the growth of new nerve fibers and increases the production of nerve growth factor in the scar itself.4PubMed Central. Mechanical tension promotes skin nerve regeneration by upregulating nerve growth factor expression This is especially true of hypertrophic scars, the raised, thickened kind. So you end up with tissue that is both stiffer than normal and more densely innervated, a combination that makes it more responsive to small changes in pressure or stretch.
Cold, Humidity, and Skin Barrier Effects
Rain rarely arrives as just a drop in barometric pressure. It usually comes alongside cooler temperatures, higher humidity, and sometimes a sharp wind chill. Each of these can independently affect how your skin and scar tissue feel.
Research on skin barrier function shows that cold and low-humidity conditions reduce the skin’s protective capacity and make it more susceptible to mechanical stress. These conditions also trigger the release of pro-inflammatory signaling molecules from skin cells and increase the number of certain immune cells called mast cells in the dermis.5Journal of the European Academy of Dermatology and Venereology. The effect of environmental humidity and temperature on skin barrier function and dermatitis Mast cells are relevant here because they play a specific and outsized role in scar tissue.
In normal wound healing, mast cells help orchestrate the inflammatory phase. But in scars, particularly hypertrophic or keloid scars, mast cells tend to be present in higher numbers and in a more activated state.6PubMed Central. The Importance of Mast Cells in Dermal Scarring When mast cells degranulate, they release histamine and inflammatory cytokines that can cause itching, swelling, and pain. Studies have shown that blocking mast cell activation in wound sites significantly reduces inflammatory cytokines like IL-1α, IL-1β, and CXCL1, and leads to less scarring overall.7PLOS ONE. Blockade of Mast Cell Activation Reduces Cutaneous Scar Formation
So when a cold front sweeps in and temperatures drop, the skin’s inflammatory machinery ramps up, mast cells become more reactive, and scar tissue, which already has more mast cells than normal skin, gets a disproportionate dose of that increased reactivity. The result is that a scar can ache, itch, or throb more intensely on a rainy, cold day than on a warm, dry one, even if the barometric pressure change alone is modest.
What Clinical Studies in Humans Actually Show
Moving from mechanisms to clinical evidence, the picture is real but complicated. A study of patients who had undergone surgery or treatment for broken bones found that complaints about weather-related pain after orthopaedic trauma are valid. The researchers concluded that while pain immediately after surgery is dominated by the surgical wound itself, over time barometric pressure, temperature, and humidity each influence pain levels.8PubMed. Nature’s wrath-The effect of weather on pain following orthopaedic trauma They recommended that clinicians acknowledge the link and counsel patients that their pain may fluctuate with weather, rather than dismissing the complaint.
This kind of finding is encouraging for people who feel their scars act up before rain, but a couple of caveats are worth noting. Most studies on weather and pain focus on joint pain, arthritis, or general chronic pain, not on scar tissue specifically. Scars share some structural and neurological features with those conditions, particularly the nerve sensitization and stiffness, but the direct evidence for isolated scar pain in response to weather is thinner than the evidence for joint-related pain. If you’ve had a surgical scar over a joint, or a fracture site that healed with significant scarring, the overlapping mechanisms make weather sensitivity especially plausible. For a small, well-healed scar on your forearm, the effect is likely much less pronounced.
How Much of It Is in Your Head
This is where the conversation gets uncomfortable for people who swear they can predict rain by their knee scar. There is a well-documented psychological component to weather pain, and it is not trivial.
A classic study tracked arthritis patients for over a year, comparing their daily pain reports to local weather data. The researchers found no statistically significant associations between each individual’s pain and the weather conditions they blamed. In a separate experiment, they showed that college students tend to perceive patterns in completely random data, finding “correlations” between unrelated sequences. The researchers argued that this tendency to see signal in noise contributes to the widespread belief that pain tracks weather.9PubMed. On the belief that arthritis pain is related to the weather
Another study found that while roughly 84 percent of subjects believed weather affects rheumatic pain, and over half claimed they could forecast weather by their symptoms, the actual statistical contribution of weather to symptom variation topped out at about 17 percent. Depression scores, on the other hand, were a significant predictor of symptoms. The researchers noted bluntly that the belief in a weather-pain connection was stronger than the statistical evidence supporting it.10PubMed. Which is the dominant factor for perception of rheumatic pain: meteorology or psychology?
This doesn’t mean weather pain is imaginary. That 17 percent contribution is real, and it lines up with the biological mechanisms described above. But it does mean that your brain is doing a lot of the heavy lifting. On a gloomy, rainy day, you’re less active, more likely to notice discomfort, and primed by a lifetime of cultural messaging to associate bad weather with aching. Confirmation bias seals the deal: the days your scar hurts and it rains are memorable, while the days it hurts on a sunny afternoon are forgettable. Over time, this selective memory builds a powerful but somewhat inflated impression of how reliably your scar predicts the weather.
Which Scars Are Most Likely to Be Weather-Sensitive
Not every scar is equally likely to flare up when conditions change. Several characteristics make a scar more prone to weather-related discomfort:
- Hypertrophic or keloid scars: These raised, thickened scars have higher nerve density, more mast cells, and greater stiffness than flat, mature scars. They are the most common culprits for weather sensitivity.
- Scars over joints or mobile areas: A scar on your knee, shoulder, or hand is already under regular mechanical stress from movement. When tissue swelling adds to that stress during a weather shift, the effect is amplified.
- Newer scars: Scars continue to remodel for one to two years after the initial injury. During that window, they are more metabolically active, more innervated, and more responsive to environmental inputs. Older, fully mature scars tend to be less reactive.
- Scars from deep injuries: Surgical scars that cut through muscle, scars over fracture sites, and deep burn scars involve more tissue layers and often more nerve disruption than superficial wounds.
Flat, well-healed scars from minor cuts rarely cause weather-related pain, which is consistent with the idea that structural abnormality and nerve involvement are the key ingredients.
What You Can Do About It
If your scar reliably aches when the weather turns, there are practical steps that can help, even if you can’t control the barometric pressure.
Keeping the scar and surrounding area warm is one of the simplest interventions. Cold temperatures contribute to mast cell activation and reduced skin barrier function, so insulating the area with clothing or a light wrap during cold, wet weather may reduce flares. Gentle massage of the scar can also help. A systematic review of conservative treatments for burn scars found that massage therapy showed positive effects on scar pliability, pain, and itching, though the evidence base was smaller than for other treatments.11PubMed. The effects of conservative treatments on burn scars: A systematic review Pressure garments and silicone-based treatments have stronger evidence for reducing scar thickness and improving pliability, which could indirectly lower weather sensitivity by making the tissue less stiff and more accommodating of minor pressure changes.
Staying physically active matters, too. People who reduce their activity on rainy days may actually experience more stiffness and discomfort, creating a feedback loop where the weather “causes” pain that is partly a consequence of immobility. Regular movement keeps blood flowing through scar tissue and maintains whatever flexibility the scar has developed.
For scars that are particularly bothersome, a dermatologist or physical therapist can assess whether the scar would benefit from more targeted intervention, such as steroid injections to reduce inflammation in hypertrophic scars, or structured scar mobilization therapy.
Why the Belief Has Persisted for Millennia
The idea that old wounds ache before rain is among the most durable pieces of folk medicine in human history. References to weather and pain appear in texts going back to ancient Greece, and expressions like “feeling under the weather” embed the association into everyday language. The persistence of this belief across cultures and centuries is striking, and it probably reflects a mix of genuine biological signal and powerful cognitive bias.
There is enough real physiology at work, the barometric pressure effect on sensitized tissue, the cold-weather inflammatory cascade, the structural vulnerability of scar tissue, that some people genuinely do experience more pain before or during storms. But the human tendency to perceive patterns in ambiguous data takes that kernel of truth and builds it into something much more reliable-sounding than the data actually support. When researchers have tested the claim rigorously, the effect sizes tend to be modest, and individual predictions turn out to be far less accurate than people believe.
The honest answer is that weather-sensitive scar pain is real but overstated. If you have a thick, raised scar over a joint, and a cold front drops the temperature and barometric pressure simultaneously, you have every physiological reason to feel more discomfort than usual. If you have a thin, old scar on your back and you’re convinced it throbs every time it rains, your brain is probably doing more of the work than the scar itself. Recognizing both sides of that equation, the genuine biology and the amplifying psychology, puts you in a better position to manage it than either dismissing the experience entirely or treating your scar like a weather station.
When Weather Pain Might Signal Something Else
Occasional weather-related aching in an old scar is rarely a sign of anything worrying. But persistent or worsening pain in a scar, regardless of weather, deserves attention. Scars can develop neuromas, small tangles of nerve tissue that form when severed nerves try to regenerate and misfire. They can also mask underlying problems in deeper structures, particularly over fracture sites where hardware like pins or plates may be irritating surrounding tissue. If your scar pain is escalating over time, present on warm and cold days alike, or accompanied by redness, swelling, or discharge, that pattern points away from weather sensitivity and toward something that needs evaluation. Weather-related scar pain is characterized by its intermittence and its link to conditions that come and go. Pain that doesn’t follow that rhythm has a different story to tell.