This may help.
''Environmental Factors
Environmental factors must be considered when working a detection dog. Working a dog in the desert with high heat hasvery different concerns when compared to working a dog in snow and very cold climates.
The best conditions for working a dog are temperatures between 40°F and 75°F, moist ground, high humidity, and a light breeze.
Although dogs can work in extreme conditions, their working time is greatly reduced.
Factors for length of time working in the field are the above-mentioned weather conditions, what scent the dog is looking for, amount of water available to the dog, and the terrain.
Live human scent is the most abundant and available scent to the dog, with prehistoric graves being the most fragile and difficult.
Fatigue is also a factor as to how long a detection dog is effective in the field. Rest and water breaks are crucial to
keeping the detection dog an effective tool. Dogs that train and work regularly will build up their scenting endurance, but, as with an athlete, you must maintain a training program to keep a high level of endurance.
For a more successful search, the dog should be allowed time to adjust or acclimatize to each new search location.
This way the dog has time to adjust to local conditions and sort out normal background scents for the new area.
This also includes letting the dog acclimatize to different weather conditions, like humidity, heat, or cold.''
(Evolution of the Historical Human Remains Detection Dog: Choosing the Best Resource
Adela Morris & Donna Randolph, Institute for Canine Forensics
Paper presented at the Society for Historical Archaeology Annual Conference, Sacramento, CA, January 11 - 15, 2006)
