Background: Investigations into drivers and barriers to the uptake of learner-centered instructional practices in STEM courses have identified the climate within a department as a potential influential factor. However, few studies have explored the relationship between adoption of learner-centered instructional practices and departmental climate around teaching. Moreover, surveys that have been designed to measure climate around teaching have been focused on measuring individual faculty member's description of their colleagues' perceptions of the climate within their department (psychological collective climate) and ignored whether there was a consensus among respondents within the same department on these descriptions. This latter measure (departmental collective climate) is best aligned with the definition of organizational climate. There is thus a need to explore whether departmental climate measured at the individual or collective level relate to the use of learner-centered instructional practices. Results: This study demonstrates that the Departmental Climate around Teaching (DCaT) survey provides valid and reliable data that can be used to measure psychological collective climate within a STEM department. Analysis of the 166 faculty members who responded to the survey indicated that: (1) four different types of psychological collective climate existed among our population; and (2) multiple types could be present within the same STEM department. Moreover, it showed that measuring departmental collective climate is challenging as few constructs measured by the DCaT survey reached high level of consensus within faculty members from the same department. Finally, the analysis found no relationship between psychological collective climate and the level of use of learner-centered instructional practices. Conclusions: Results from the validation studies conducted on the DCaT survey that most elements that define a climate (e.g., policies, practices, expectations) are lacking when it comes to teaching. These findings could explain the challenges experienced in this study in measuring departmental collective climate. Without these climate elements, faculty members are left to work autonomously with little expectations for growth in their instructional practices. Establishing policies, practices, and expectations with respect to teaching is thus an essential step toward instructional change at a departmental level.