Calibration of devices recording environmental conditions during calibration

Hello,
I have a question regarding calibration of devices, which are used for recording of environmental conditions during calibration.

In NIST Handbook and in ISO/IEC 17025 is written, that environmental conditions have to be included in calibration report.
Unfortunately I haven’t found a statement, if the equipment measuring/recording this environmental conditions must be also calibrated, or if it is only an additional information in calibration report.

Please, could you help me to find, where is defined that these devices has to be also calibrated?

Thanks in advance.

According to ISO17025 also equipment for measurement of environmental conditions must be calibrated if environmental conditions have major effect to final results:
" All equipment used for tests and/or calibrations, including equipment for subsidiary measurements (e.g. for
environmental conditions) having a significant effect on the accuracy or validity of the result of the test,
calibration or sampling shall be calibrated before being put into service."

Thank you a.danihlik, this is exactly, what I was looking for.