SPMV scale rates Thermal Comfort from -4 (cold) to +4 (warm) and typically the blue range, between -1 and 1, is considered comfortable and the blue and yellow rate between -2 and 2 is considered acceptable.

[-1,1] is Percent of Time Comfortable (% of time within the bounds of being comfortable)

[-2,2] is Percent of Time Acceptable (% of time within the bounds of being comfortable or
acceptable)

For more information check out: https://help.orbitalstack.com/thermal-comfort-spmv-hot-color-legend-hot-and-tropical-climates-explained/