CONSULTANCY - Senior Full-stack Software Developer - Climpact Modernization - SSA 2026-CRI-SSCD-4

Background

Climate science information plays a critical role in supporting evidence-based climate adaptation, risk management and sustainable development. The effective use of climate observations, analyses and indices enables National Meteorological and Hydrological Services (NMHSs) to contribute more effectively to national planning and decision-making processes, particularly the development and implementation of National Adaptation Plans (NAPs) and Nationally Determined Contributions (NDCs). Strengthening NMHSs' capacity to generate and communicate reliable climate science information is therefore essential to informing climate-resilient policies, sectoral services and engagement, and investment decisions. 

To strengthen the capacities of Members, particularly in Least Developed Countries (LDCs) and Small Island Developing States (SIDS), the WMO has organized more than twenty training workshops on Climate Science Information for Climate Action (CSICA) and related topics over the past decade. These workshops provide practical methodologies and hands-on training in climate data quality control and homogenization, climate indices calculation, co-creation cross sectors, and the interpretation and application of climate information for adaptation planning and climate services. Climpact has been a core software tool supporting these activities, enabling NMHSs to the best-available climate science information, calculate climate indices and generate information relevant to national and sectoral planning.

Climpact evolved from international efforts to standardize climate extremes indices, initially advanced through the Working Group on Climate Change Detection (WGCCD) and subsequently the Expert Team on Climate Change Detection and Indices (ETCCDI). Building on RClimDEX, Climpact incorporated both core climate extremes indices and sector-specific indices to support the growing demand for climate services. Over recent years, feedback from workshop participants and NMHSs has highlighted a growing need to modernize Climpact and improve its functionality, accessibility and user experience. In particular, the online version faces performance and stability challenges in countries with limited internet bandwidth, while the desktop version requires complex installation and dependency management, posing difficulties for users, particularly those working in Windows environments. Members have also expressed the need for more efficient quality control workflows, improved visualization and greater flexibility to incorporate new scientific functions. These challenges have reinforced the need for a more reliable, user-friendly and sustainable software platform.

This consultancy is looking for a full-stack developer to redesign the Climpact web portal. The redesigned portal should consist of a Python-based backend for calculating climate indices (based on user-provided climate data), and a front-end based on the latest internet standards for accessibility and security. Key priorities are interactive visualisations, bandwidth efficiency, low maintenance and modular code, scalable performance, containerization and an emphasis on open-source technologies.  In parallel, the consultant is also expected to work with climate indices scientific community on the scientific computing of climate indices. 

Duties and Responsibilities

The Consultant will work under the overall supervision of the Chief of the Climate Research and Information Section and will report monthly to the Junior Professional Officer of the Section. The Consultant shall work collaboratively with WMO staff and external Climpact experts on technical requirements, software integration and scientific consultations. The development process will follow an iterative approach, with periodic joint reviews, testing and revisions coordinated by the WMO Secretariat. Under this structure, the consultant will:

1. Review the existing Climpact software, including its source code, architecture, dependencies, scientific calculation modules, user interface and deployment arrangements, and identify technical limitations and opportunities for modernization and reuse of existing components.
2. Design a modern, modular, and maintainable back-end architecture for the upgraded Climpact, leveraging established open-source scientific computing libraries, particularly the Python-based xclim package. Define the core framework, data processing workflows, module interfaces, and integration strategy, ensuring compatibility with existing and future scientific functions.
3. Develop and implement the core software functions, supporting climate data calculation workflows for station-based and gridded datasets, and enabling the modular integration of quality control, climate indices calculation and homogeneity assessment functions in collaboration with WMO climate indices experts. 
4. Develop a user-friendly front-end with interactive visualizations, enabling users to upload and process climate datasets, select and calculate climate indices, visualize results through appropriate plots and download outputs in commonly used formats.
5. Deploy the portal to a suitable online platform (e.g. Amazon web services), ensuring that the architecture supports a streamlined offline deployment option. Particular consideration should be given to accessibility, ease of installation, low-bandwidth environments, and software reliability.
6. Conduct technical testing and quality assurance, including unit and integration testing, verification of data processing workflows, and testing of selected climate indices calculations. Identify and address technical errors and compatibility issues arising during development.
7. Prepare technical documentation, and facilitate handover and validation, including the software architecture, source code repository, module interfaces, installation and deployment instructions, testing results, and recommendations for future development. Collaborate closely with WMO Secretariat and clim

Main deliverables

1. Inception report and software architecture design, including review of the existing Climpact codebase and dependencies; proposed Python-based architecture; modular framework, data processing workflows and interfaces for scientific functions; and detailed development workplan. (Estimated 7 working days)
2. Functional core software framework construction, supporting climate data processing and calculation workflows for station-based and gridded datasets, with a modular structure accommodating quality control, climate indices calculation and homogeneity assessment functions. (Estimated 10 working days)
3. Integration of initial scientific functionalities, including the existing quality control module and a selection of climate indices available through xclim. (Estimated 8 working days) 
4. User interface and visualization functions, enabling climate data upload, selection and calculation of climate indices, interactive visualization of results, and export of outputs in commonly used formats. (Estimated 7 working days)
5. Online deployment of the initial Climpact application, integrating the developed software framework and essential functionalities, with consideration for accessibility, low-bandwidth environments, system stability and future offline deployment compatibility. (Estimated 5 working days) 
6. Technical testing, documentation and handover, including unit and integration testing, verification of essential workflows, resolution of identified technical issues, source code and repository documentation, deployment instructions, and recommendations for further development and scientific validation. (Estimated 3 working days)

Required Skills and Experience

Education: A university degree (Bachelor's or Master's) in Computer Science, Software Engineering, Information Technology, Data Science, or a closely related field.

Experience:

• At least five years of full-stack experience demonstrated in designing, implementing and deploying modular and scalable web-based applications, preferably involving scientific computing, to platforms such as Amazon web services.
• Proven experience in Python programming and developing modular, containerized and maintainable software applications using open-source libraries and frameworks. 
• Experience in developing user-friendly web interfaces with a focus on data visualization functions and interactive data-processing workflows.

Other Requirements: 

1. Familiarity with scientific computing libraries such as NumPy, pandas and xarray. Experience with climate data processing and visualisation, particularly including xclim or similar libraries would be an advantage.
2. Experience working with time-series and gridded datasets, particularly NetCDF or other climate and environmental data formats, would be an advantage.
3. Knowledge of R programming and experience integrating R-based functionalities into Python applications would be an advantage.
4. Good understanding of software quality assurance, dependency management, automated testing and open-source development practices.
5. Strong analytical and problem-solving skills, with the ability to work independently, communicate effectively with scientific experts and deliver results within agreed timelines.

Languages: Excellent command of written and spoken English required. Knowledge of another UN language is an asset. (Note: the official languages of the Organization are Arabic, Chinese, English, French, Russian and Spanish.)

Salary and Allowances:  Pay band C - USD 390.- / USD 560.-

Duration: 40 days over a period of 6 months

Focal point: Xinrui WU, xwu@wmo.int 

Applications:

Applications should be made online through the WMO e-recruitment system.

Do not send your application via multiple routes. WMO no longer accepts applications via post or email. Only applicants for whom WMO has a further interest will be contacted. Shortlisted candidates may be required to sit a written test and/or an interview.

Statements:

WMO is committed to achieving diversity and a balanced workforce. Applications are welcome from qualified women and men, including those with disabilities. The statutory retirement age is 65. Pursuant to WMO Standing Instructions, the minimum age to be eligible for consideration for vacant positions is 18, and the maximum age must enable the candidate to serve for at least the term of the contract before reaching mandatory age of separation.

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