Definition of «warm phase»

The phrase "warm phase" means a period of time when conditions or temperatures are higher than usual.

The starting points are pinned at zero, except for the global warming phase which was pinned at minus 10 degrees C. (co2coalition.org)
For warm phase, the range of probabilities is larger. (aoml.noaa.gov)
Exactly when did said warming phase start, and when will it end? (wattsupwiththat.com)
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