What does it take to keep the world in sync?

In the cool, high-altitude labs of CENAM in Querétaro, Mexico, timekeepers gathered not just to learn—but to connect, collaborate and reimagine their role in the global fabric of timekeeping.

The BIPM–SIM UTC Summer School, held in May and hosted by Mexico’s National Metrology Institute (CENAM), brought together participants from 18 countries for three days of expert-led training and technical exchange. The initiative is part of the BIPM’s ongoing efforts to build capacity and support global contributions to Coordinated Universal Time (UTC)—the time standard that underpins everything from energy grids to satellite navigation.

Caption: Participants in hands on tutorials and going on lab visits. Photo credits to Tara Fortier of the BIPM and Carlos Andres Ortiz Cardona of CENAM Mexico

Why It Matters

Across much of the SIM region, National Metrology Institutes (NMIs) have identified and expressed the need to address many of the same challenges: limited access to advanced infrastructure, constrained travel budgets, and a shortage of trained personnel to support ongoing UTC participation.

In response to these challenges, the BIPM–SIM UTC Summer School offered a blended programme of tutorials, lab demonstrations and peer learning. It gave career professionals the technical grounding, practical tools and community support to take on a greater role in UTC activities.

Participants trained in:

• GNSS time transfer and receiver calibration
• Timescale generation and analysis
• Time service distribution and national applications

This international effort was made possible thanks to the combined contributions of three key organizations—CENAM, the BIPM and the IEEE UFFC Society—each playing a vital role in delivering, hosting and expanding access to the programme:

• CENAM: CENAM’s laboratories provided a live, hands-on environment—introducing not only current best practices, but also emerging optical technologies that are key to the upcoming redefinition of the SI second.
• BIPM: The BIPM’s CBKT e-learning platform supports the learning journey beyond the event, offering online tools and education resources that participants can access for free from their home institutes.
• IEEE UFFC Society: Finally, the IEEE-UFFC-Society programme enabled broad participation, by providing travel support to NMIs where needed.
   

Caption: Group photo of participants and instructors at the BIPM–SIM UTC Summer School 2025, held at CENAM in Querétaro, Mexico.Photo credit to Tara Fortier of the BIPM

More Than a Course

While the technical content was robust, what participants valued most was the human connection.

“Participating in the SIM-BIPM Summer School was a great opportunity not only to stay up to date with the latest works in the Time and Frequency international community but also to share the knowledge and experiences each laboratory has on the road to developing their UTC(k). It was also a great opportunity for networking with colleagues and strengthening the ties within the SIM Time and Frequency community,” — Raul Solis, Metrologist at CENAMEP AIP

Structured networking sessions, shared meals, and cross-institute conversations all fostered a sense of purpose and collaboration—building a community of practice that extends well beyond the closing session.

As the BIPM celebrates its 150th anniversary, initiatives like the UTC Summer Schools underscore its enduring role: enabling all countries to contribute meaningfully to the world’s measurement systems and ensuring timekeeping remains a truly global endeavour.