Posted on: 12/06/26

Summer is the season when temperature-controlled storage is put under the greatest strain. Equipment works harder, ambient conditions become less predictable and the margin between compliant and non-compliant storage narrows. For organisations storing medicines, vaccines, blood products or research samples, that's not an inconvenience - it's a patient safety and compliance issue.
Here's why summer presents a genuine risk to temperature-controlled storage and why a temperature mapping study should be on your checklist before the heat peaks.

The problem starts outside

When outdoor temperatures rise, the knock-on effect inside a facility can be significant. Buildings absorb heat, air conditioning and ventilation systems run at full capacity and the temperature in your storage areas may become less stable.

Refrigeration equipment faces a more direct challenge. A pharmacy fridge or cold room must maintain 2°C to 8°C regardless of the surrounding room temperature. In summer, particularly during a heatwave, that becomes significantly harder to achieve.

Equipment that performs well in winter can fail in summer

This is one of the most common surprises organisations encounter when they carry out a summer temperature mapping study for the first time.

A fridge that has been running within range all year can develop hot spots in summer that push certain zones above the required limit. The display temperature is measured at a single fixed sensor and may not reflect what is happening in the corners, near the door seal or at the top of the unit.

The reasons are straightforward. As ambient room temperature rises, the thermal load on the unit increases. The compressor works harder and generates more heat, door openings let warm air in and any weakness in insulation or door sealing that went unnoticed in cooler months will become apparent.

Why regulators require more than a monitoring system

Under MHRA GDP Guidelines and EU GDP Guidelines for those exporting to Europe, organisations storing medicinal products are required to maintain storage conditions within defined limits at all times, regardless of external weather conditions. This includes demonstrating, through documented evidence, that storage areas remain compliant during periods of seasonal stress.

Temperature mapping is the primary tool for generating that evidence. Unlike a fixed monitoring sensor, which only records conditions at a single point, a mapping study places data loggers throughout the storage area, giving you a complete thermal profile of how every zone performs under real summer conditions. It identifies any areas that breach required limits and provides the documentation regulators expect to see.

What good summer preparation looks like

Organisations that manage summer risk well tend to do a few things consistently:

Map before the heat peaks. A temperature mapping study carried out during early summer gives you time to act on the findings - adjusting sensor positions, servicing equipment, or reorganising product placement - before the hottest weeks arrive.

Review previous monitoring data. Summer alert patterns from previous years are a reliable guide to where the risks in your facility lie. If the same fridge generates excursion alerts every July, it is worth investigating further.

Don't assume last year's results still apply. Equipment ages. Building usage changes. Air‑conditioning systems degrade. Air conditioning systems degrade. A mapping study from two or three years ago may not reflect how your storage environment performs today.

Treat summer as a distinct risk period. The organisations that stay consistently compliant are those that plan for summer in the same way they plan for any other operational risk, with documentation, scheduled reviews and a clear process for acting on what they find.

How Contronics can help

Contronics is a UKAS-accredited ISO 17025 temperature mapping service provider working with hospital pharmacies, NHS Trusts, blood banks, laboratories and pharmaceutical organisations across the UK.

Our summer temperature mapping studies are carried out by experienced field engineers using calibrated data loggers. We use 11 per fridge, compared to the 9 many providers use, plus a door status logger where required. Units remain in service throughout the study. You receive a comprehensive report covering hot and cold spot locations, ambient conditions throughout the study period and recommendations for sensor placement and storage practice.

To find out more or to book a summer mapping study, please contact our team.