Various temperatures relative to a 25 degrees C control have been applied as phase-resetting agents in release-assay experiments using the conidiation rhythm of the mold Neurospora crassa. The larger the difference in temperature from the 25 degrees C control, the stronger the phase-resetting effects. Phase-resetting curves of the weak type (type 1) are observed for temperatures up to 28 degrees C and down to 22 degrees C, whereas temperatures above 28 degrees C and less than 22 degrees C generally cause phase-resetting curves of the strong type (type 0). Singularity behavior occurs at approximately 22 degrees C and 28 degrees C when 25 degrees C is used as the control temperature. When a different control of 29.5 degrees C is used in a release-assay experiment and the resetting temperature is 25 degrees C, near-singularity behavior is observed.