Arid

This climate is generally very dry, however, in arid areas, it is often very hot during the day and very cold at night. This wide fluctuation in temperature is matched by wide fluctuations in relative humidity, for example, from 75%–20% in a day.

When caring for outdoor materials in arid areas it is important to note that:

• insects can still survive;

• wood moved from more humid climates may be prone to cracking and splitting; and

• condensation may form on metal objects which become very cold overnight.

Dust storms effectively sandblast outdoor objects. It is worth considering strategic placement of windbreaks to prevent damage. If the objects are small enough you may want to have covers made. The covers can be put in place during periods of high wind.

Remember also that outdoor objects can be adversely affected by the dust raised when vehicles travel over dirt roads. Similar steps as those taken for preventing damage from dust storms should be considered.

If the area is very dusty, you may need to inspect items for dust and dirt build-ups, especially in periods of low rainfall.

Note: If your collection of outdoor cultural materials have been displayed in an arid environment for a considerable period and they are stable—do not try to alter the environment to meet the recommended ideal conditions. This could do more harm that good. The emphasis should be on long term stability.

Temperate

As climate is considered a moderate climate, however, temperate climates tend to have a greater range of temperatures than tropical climates and may include extreme climatic variations.

When caring for outdoor cultural material in temperate climates it is important to note that:

• freezing conditions will occur in some regions. Where water has entered cracks in stone and wood, freezing conditions can lead to splitting. Ice takes up more space than water and thus as the water freezes it opens up cracks in the material;

• seasonal fluctuations can lead to the splitting of wood; and

• extended rainy periods can accelerate corrosion in metals and can promote the growth of lichens, mosses etc.

Note: If your collections of outdoor cultural material have been displayed in a temperate environment for a considerable period and they are stable—do not try to alter the environment to meet the recommended ideal conditions. This could do more harm than good. The emphasis should be on long term stability.

Tropical

These climates are characterised buy heavy rainfall, high humidity and high temperatures.

When caring for outdoor cultural materials in high humidity conditions, it is important to note that:

• insects, lichens, moulds and plants thrive and reproduce rapidly;

• metal corrosion will be accelerated;

• wooden components of objects will take up water and hold it. If the wood is in contact with metal components, metal corrosion will proceed faster in these areas; and

• deterioration, particularly of plastic components, due to light and UV radiation will be accelerated.

Because the rate of deterioration is likely to be quite rapid, it is important to check items for damage and carry out maintenance more regularly than in other climatic zones.

Carry out the maintenance of coatings on metal components during the dry season, when there is less moisture present. In this way you are less likely to trap moisture between the coating and the metal.

Note: If your collections of outdoor cultural material have been displayed in a tropical environment for a considerable period and they are stable—do not try to alter the environment to meet the recommended ideal conditions. This could do more harm than good. The emphasis should be on long term stability.

Coastal Regions

Coastal regions generally have more moderate climates than inland areas but they also have high levels of wind-borne salt. Consideration must be given to counteracting the corrosive effects of salty air.

When caring for outdoor cultural materials in coastal regions it is important to note that the presence of moist salty air is going to lead to high levels of corrosion and damage from windborne particulates.

It is, therefore, vital that metal components are treated, coated and frequently inspected in these conditions.

Take all steps possible to reduce water retention. These steps include ensuring there is good drainage and clearing weep holes.

It is better to display outdoor cultural material away from the sea front. Windbreaks would also assist in protecting items.

It is important to monitor items for the formation of salt crystals, and concrete and stone should be check for spalling.

If you have a problem related to the care of outdoor cultural material contact a conservator. Conservators can offer advice and practical solutions.