Wood is sensitive to moisture, and keeping a classical guitar within a healthy humidity range is one of the simplest things an owner can do to protect an instrument for decades. This guide from LG Guitar Guide covers the humidity levels worth aiming for, why Finnish winters are a particularly demanding season for wooden instruments, and the basic care routine that keeps a guitar sounding and playing well.
The right humidity range
A commonly recommended humidity range for a wooden guitar is roughly 40 to 60 percent relative humidity. Below that range, wood begins to dry out, shrink, and build internal stress, which can lead to cracking, especially in the top and back plates. Above that range, excess moisture can soften glue joints, raise the risk of mould, and make the tone sound dull and less responsive. The goal is to stay within that fairly narrow but important band as consistently as possible, all year round.
Why Finnish winters are hard on guitars
Central heating during the Finnish winter dries indoor air considerably - cold air outside combined with heating indoors can push relative humidity down to levels far below what a wooden guitar needs to stay stable. This is one of the main reasons sudden cracks tend to show up in winter, in instruments that were perfectly fine all summer. A guitar kept in a home where the winter air is very dry faces a noticeably higher risk than one kept somewhere with more stable conditions.
Humidifiers and hygrometers
A soundhole humidifier, placed inside the sound hole or inside the case, is a simple and affordable way to keep the air immediately around the guitar more stable, particularly when the instrument spends most of its time in its case. Alongside a humidifier, a dedicated hygrometer is worth having, since it shows the actual humidity level near the guitar rather than relying on guesswork. The humidity reading for a room in general and the humidity inside a closed case can differ noticeably, so a case-level reading is far more useful in practice.
What winter cracking typically looks like
Cracks caused by dryness usually run with the grain of the top, often near the bridge or along the centre seam. They happen when the wood shrinks unevenly and the resulting stress exceeds what the wood can handle. These cracks are best addressed as soon as they are noticed, since they tend to widen further if the guitar keeps sitting in overly dry conditions without being repaired.
Basic cleaning and upkeep
Cleaning a classical guitar does not require specialised products. Wiping down the top and neck with a soft, lint-free cloth after playing removes sweat and oil that would otherwise build up over time and affect the finish and the fingerboard. Harsh cleaners or solvents are best avoided on a lacquered finish unless you are certain they are compatible with that particular coating.
Changing strings
How often to change strings depends heavily on how much the guitar gets played. A musician practising daily may notice strings losing brightness and accurate intonation within a few weeks, while an occasional player might get several months out of the same set. Signs that a change is due include a duller tone, less precise intonation, and a rougher feel under the fingers.
Related reading
If you are curious about how different tonewoods and construction choices affect how sensitive a guitar is to humidity, our page on materials goes into more detail. And if you are weighing up buying a used instrument, the guide on second-hand guitars covers exactly what to check before you commit.
