A thermal proxy device for monitoring change in condition. The change in condition can be a change in temperature such as a change above or below a predetermined temperature or a freezing condition. An indicator used in the thermal proxy device can have the same physical-chemical properties as the product to be monitored. The indicator can have a similar thermal mass with similar specific gravity and/or specific heat of the material to be monitored. The indicator can be associated with a container of the material to be monitored.