The eye's surface is exposed to the environment with every blink. Wind and cold air act directly on this surface, destabilising the tear film and stimulating sensory nerves in and around the eye. The result is a reflex, the lacrimal gland responds by producing more tears, more quickly than the drainage system can remove. This overflow is the watering that most people experience outdoors. It is a normal physiological response, though its intensity varies considerably between individuals and tends to increase with age.
- Wind accelerates evaporation from the tear film
- Cold air dries and destabilises the tear film
- Sensory nerves in the eye and face trigger a reflex tear response
- Dry eye makes all of these effects more pronounced
- Age-related changes to eyelid tone reduce drainage efficiency
The trigeminal nerve supplies sensation to the eye's surface, the eyelids, and much of the face. When this nerve is stimulated by cold air, wind, bright light, or irritation, one of its responses is to signal the lacrimal gland to produce more tears. This is a protective reflex: extra tears wash and rehydrate the eye's surface in response to environmental stress. The system is well-designed for its purpose but somewhat indiscriminate, it produces reflex tears whenever it senses threat to the eye, including relatively mild threats such as a cold breeze. The tears produced in this way are watery and lacking in the oil and mucin components of a stable tear film, which is partly why they do not resolve the situation, they overflow rather than coat the eye effectively.
See watery eyes explained for more detail.
Many people who water significantly outdoors have an underlying dry eye component that they may not have recognised as a formal problem. When the tear film is already borderline unstable, any additional environmental stress, wind, cold, bright sunlight, tips the balance more readily. The outdoor environment reduces the blink rate (people tend to squint and blink less in bright light), which means the tear film is refreshed less often and evaporates more quickly. This is why lubricating eye drops used before going outside can significantly reduce outdoor watering in susceptible patients.
See can dry eyes cause watery eyes for more detail.
The lower eyelid serves as both a windbreak and a drainage pump. It diverts some of the direct wind exposure away from the eye's surface, and its muscle (the orbicularis) pumps tears through the drainage system with each blink. With age, the lower eyelid loses muscle tone and may sag slightly. This means it is less effective as a windbreak and less efficient as a drainage pump. Even a small degree of eyelid laxity, often not noticeable to the patient, can significantly increase the sensitivity of the eye to outdoor conditions.
See ectropion and entropion and watery eyes in older adults for more detail.
Preservative-free lubricating eye drops used before going outside stabilise the tear film and reduce its sensitivity to wind and cold. They work by supplementing the natural lipid and mucin components that make the film resilient. Used regularly, not only when symptoms are present, they often produce a sustained improvement rather than only short-term relief. Simple protective measures and appropriate lubricants address most outdoor watering without any need for formal intervention.
Last medically reviewed: May 2026
Written by Chris Matthews, Consultant Ophthalmologist and Oculoplastic Surgeon.
This page is written for general educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. If you have concerns about your eye health, please consult a qualified healthcare professional. In an emergency, contact your nearest urgent eye care service or emergency department.
