IP Ratings Explained (IP65 vs IP66 vs IP67 vs IP68)
An IP rating has two digits: dust protection, then water protection. Most sensors in this range carry IP67 for general housing and IP68 for pressure-sensing elements specifically, because those components use different sealing methods.
What the two digits mean
An IP (Ingress Protection) rating has two digits. The first digit (0-6) rates protection against solid objects and dust, where 6 means fully dust-tight. The second digit (0-9) rates protection against water, where 6 means protection against powerful water jets and 8 means protection against continuous submersion. IP67 means dust-tight and protected against temporary immersion up to 1 metre; IP68 means dust-tight and protected against continuous submersion beyond 1 metre, to a depth and duration the manufacturer specifies.
Why one sensor can have multiple IP ratings
Sensors in this range often carry different IP ratings for different internal components. A compact weather sensor such as the ZWS600 is rated IP67 for its temperature and humidity elements but IP68 for its pressure sensor, because the pressure-sensing element uses a different sealing method than the temperature/humidity module. When you see two ratings listed for one product, that's why: it's not a typo, it reflects genuinely different sealing on different internal parts.
IP55 vs IP65 vs IP66 vs IP67
IP55 protects against dust ingress (not fully dust-tight) and low-pressure water jets from any direction, adequate for an outdoor enclosure that is otherwise sheltered. IP65 is fully dust-tight with the same water jet protection. IP66 steps up to powerful water jets. IP67 adds temporary submersion resistance. Outdoor air quality stations in this range (the ZAQ series) typically use IP55 for the outer cabinet with IP67/IP68 for the individual sensing elements inside, since the cabinet itself doesn't need submersion resistance but its internal sensors do.
What this means for buyers
Match the rating to the actual exposure, not just "outdoor use". A sensor mounted under an eave rarely needs IP68. A sensor mounted on an exposed coastal mast in driving rain benefits from the higher water-jet ratings (IP66/IP67). Submersible water quality probes are the one category in this range where IP68-class continuous-immersion sealing is the baseline requirement, not an upgrade.
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Frequently asked questions
Is IP68 always better than IP67?+
For submersion resistance, yes, IP68 tolerates continuous submersion beyond 1 metre while IP67 tolerates only temporary immersion to 1 metre. But IP68 isn't automatically necessary: a sensor that will never be submerged doesn't need it, and choosing it doesn't improve dust protection since both share the same top dust-protection digit (6).
Why does one product page list two different IP ratings?+
Because different components inside the same housing can be sealed differently. A compact weather sensor's temperature/humidity module and its pressure-sensing element are physically separate parts that can carry separate IP ratings, both listed on the same product page.
What IP rating do outdoor air quality stations use?+
Typically IP55 for the overall cabinet, since it houses electronics that don't need full dust-tightness or submersion resistance, with IP67 or IP68 on the individual temperature/humidity and pressure sensing elements inside.