INRIM laboratories develop and maintain primary standards of humidity to disseminate the frost- and dew-point temperature scales in the range between -105 °C and 140 °C, over an extended range of pressure (from below atmospheric up to 0.6 MPa). The recent extension of the frost-point temperature scale studies allows to provide measurement traceability for trace humidity in pure gases and energetic gases. Relative humidity and air temperature standards are also realized and maintained for industrial and scientific applications.