Considering that nearly half (40%-50%) of the photovoltaic (PV) plants are less than just 5 years old, the cumulative knowledge and return-of-experience (REX) from PV operations and maintenance (O&M) are at their relative infancy; particularly where it relates to the impact of different climatic profiles on the budgeting, technical risks and customization of PV O&M. Besides, one of the main challenges in tailoring O&M for a specific PV application in a certain climate zone is the present scarcity of comprehensive guidelines and/or standards, which only clarify the minimum requirements of climate-specific O&M and their implementation. Recently, experts of the IEA PVPS Task 13 have gleaned best practices and guidelines for O&M in different climate zones/profiles, covering all key aspects of the typical PV O&M agenda, based on field experiences of the contributing PV and O&M experts from multiple countries representing the climate zones addressed. In this paper, we provide the key findings of this work: a comprehensive guide on setting up a customized O&M practice for PV plants in seven different climate zones, four of which are general (moderate, hot and dry, hot and humid, desert in high elevation), and three which are more specific to extreme conditions (flood-prone region, cyclonic region, snowy region). In terms of novelty, we particularly emphasize on (existing and new) knowledge and practices for PV O&M in the last three climatic profiles/regions, which present distinct challenges from a PV performance and reliability point of view. As such, the climate-specific O&M guidelines presented in this report aim to serve different functions to various stakeholders depending on their roles in the entire value chain of PV.