Precipitation and temperature minimum and maximum are key climate factors affecting plant growth and development. Annual, seasonal, and monthly precipitation can be used to evaluate species suitability. Water balance information would be ideal (precipitation received, amounts lost from run-off and deep percolation and from evapotranspiration), but lesser detail can be useful in initial estimates. Minimum and maximum temperatures are normally found in January and July, respectively, so these have been chosen for plant suitability criteria.

Other factors like solar radiation, relative humidity, and wind speed may be helpful additions as these data become available.