Temperature fluctuation is the rise and fall of temperature in a space over hours, days or seasons. In storage, the swing itself matters less than what it does to the air: as temperature falls, relative humidity rises, and a large enough drop brings condensation. Materials also expand and contract as they warm and cool.
At Wigwam
Our units aren't heated, cooled or climate-controlled, so the temperature inside isn't regulated. We don't publish a temperature range for any site. Our terms don't allow portable heaters (clause 19) and there's no power for your use (clause 22(e)), so how your things are prepared is what protects them. Our terms also make it your job to be sure the unit suits what you store (clause 26).
What swings do
The Canadian Conservation Institute gives the scale: a 1°C fluctuation causes about a 3% swing in relative humidity, a 5°C fluctuation about 15%, and a drop of more than 10°C can take air to 100% and condensation: air at 50% relative humidity cooled by 10°C reaches 100%. Museums Galleries Scotland notes that fluctuating humidity caused by temperature changes makes decay in textiles worse, as fibres swell and shrink. Veneer can lift as it swells, then set out of shape. Papers and photographs age through warmth as well: for chemically unstable materials, the same institute's rule is that each 5°C reduction doubles the object's lifetime, so a warm summer adds up over years. Our guide to storing photographs, negatives and old film goes further.
In practice:
- drain washing machines and dishwashers, since water left inside can freeze;
- pack clean and fully dry, off the floor, with a gap at the walls;
- look in after a hard frost or a hot spell. Access is 6am to 10pm, seven days a week.
Our winter and summer guide goes through common items one by one, from TVs to candles.
Related terms: Condensation · Relative humidity · Heated storage
Related questions: Do storage units get cold in winter or hot in summer? · Are storage units waterproof?