To read humidity datalogger data accurately, you need to access the recorded sensor log, verify the device was calibrated correctly before shipment, and review the readings in the context of the conditions the logger experienced during transit. Accuracy depends on both the quality of the humidity sensor and how the logger was handled, stored, and activated. The sections below walk through what the data shows, how to access it, what affects its accuracy, and how to interpret whether readings fall within acceptable limits.
What does humidity datalogger data actually show?
Humidity datalogger data shows a time-stamped record of relative humidity (RH) levels measured at regular intervals throughout a shipment or storage period. Each data point pairs a humidity reading with the exact time it was recorded, giving you a complete picture of how moisture conditions changed from the moment logging began to the moment the device was read.
Most humidity data loggers also capture temperature alongside humidity, because the two are closely linked. Relative humidity is a measure of how much moisture the air holds compared to its maximum capacity at a given temperature. When temperature shifts during transport, the relative humidity reading shifts with it, even if the absolute moisture content in the air stays the same. This is why reviewing humidity sensor data in isolation from temperature can be misleading.
A typical humidity log will include:
- The start and end time of the logging period
- The measurement interval (for example, every 5 or 15 minutes)
- The minimum, maximum, and average RH percentage recorded
- A full time-series log of every individual reading
For perishable goods such as fresh produce, flowers, or pharmaceuticals, this data is essential for understanding whether conditions stayed within the range that protects product quality throughout the cold chain.
How do you access the recorded data from a humidity datalogger?
How you access humidity datalogger data depends on the type of logger used. Electronic single-use loggers typically require a USB connection to a computer or a Bluetooth link to a dedicated app, after which the data is exported as a PDF or CSV file. Reusable electronic loggers follow a similar process. Paper-based loggers, by contrast, use NFC technology and can be read with a smartphone tap, with no app or hardware required.
For USB-based electronic loggers, the retrieval process involves plugging the device into a computer, opening the manufacturer’s software, and generating a report. This creates a dependency on specific hardware and software being available at the receiving end, which is not always practical in international supply chains where partners may not have the right setup.
Tapp’s paper-based data loggers take a different approach. Because they use NFC smartphone tap technology, any NFC-enabled smartphone can read the label instantly. The data is automatically uploaded to the cloud the moment the label is tapped, making the full humidity and temperature log available to both the sender and the receiver without any additional infrastructure. This removes the access barrier that often slows down cold chain humidity monitoring in practice.
Regardless of the method, the key principle is the same: the data should be accessed as soon as the shipment arrives so that any deviations can be identified and acted on quickly.
What affects the accuracy of humidity datalogger readings?
Several factors influence how accurately a humidity data logger captures real-world conditions. The most important are sensor quality, calibration status, logger placement, and battery performance during the recording period.
Sensor quality and calibration
Humidity sensors degrade over time, particularly when exposed to condensation, chemical vapors, or extreme temperature swings. A sensor that was accurate when manufactured may drift if it has not been recalibrated or replaced. Before relying on any humidity datalogger reading, it is worth confirming that the device was calibrated within the manufacturer’s recommended period. Single-use loggers are typically factory-calibrated and used once, which eliminates drift from repeated use.
Placement and environmental interference
Where the logger sits inside a shipment matters significantly. A logger placed directly against a cold surface or near a ventilation point will record different humidity levels than one positioned in the center of the load. For the most representative reading, the logger should be placed in the zone most representative of the product’s actual environment, not in a corner or against the packaging wall.
Battery performance is another factor that is often overlooked. If a logger’s battery drains before the shipment ends, the recording stops and data is lost for the remainder of the journey. Paper-based loggers have an advantage here because their lithium-free battery design is optimized for the duration of a single shipment, with no risk of partial discharge from prior use or recharging cycles affecting performance. Electronic reusable loggers, by contrast, depend on the battery being adequately charged before each trip, which introduces a variable that can compromise data completeness.
How do you know if the humidity readings are within acceptable limits?
To determine whether humidity readings are within acceptable limits, compare the logged data against the specified humidity range for the product being shipped. Acceptable limits vary widely by product type: fresh flowers typically require high relative humidity to prevent wilting, while some pharmaceutical products require tightly controlled low-humidity environments to prevent moisture damage.
When reviewing a humidity log, look for three things:
- Peak excursions: Were there any readings that exceeded the upper or lower humidity threshold, even briefly? A short spike can be significant for sensitive goods.
- Duration of excursions: A single out-of-range reading may be less concerning than a sustained period above or below the limit. Review how long the humidity stayed outside the acceptable range.
- Correlation with temperature: Cross-reference humidity readings with temperature data. A humidity excursion that coincides with a temperature drop may indicate condensation risk rather than a change in the ambient moisture environment.
Most cloud-based reporting tools will flag excursions automatically and display summary statistics, making it straightforward to see at a glance whether the shipment stayed within range. The key is ensuring the acceptable limits are set correctly in the system before the shipment departs, so the comparison is meaningful when the data is reviewed on arrival.
How Tapp helps with humidity and temperature monitoring
Reading humidity datalogger data accurately starts with using a logger that captures clean, reliable data and makes it easy to access. Paper-based data loggers address the most common friction points in cold chain humidity monitoring:
- No USB or app required: Any NFC-enabled smartphone reads the label instantly, removing access barriers at the receiving end
- Automatic cloud upload: The full humidity and temperature log is available to both sender and receiver the moment the label is tapped
- Lithium-free battery: Optimized for single-use shipments with no risk of partial discharge affecting data completeness
- Sustainable by design: Made from agricultural waste paper and recyclable through standard paper waste streams, reducing e-waste compared to electronic single-use loggers
- EN12830-certified accuracy: Professional-grade sensor accuracy that supply chain teams can trust across all transport modes
If you want to simplify how your team reads and interprets humidity sensor data across your supply chain, get in touch with Tapp to find out how paper-based monitoring fits your shipments.
