When surveying in extreme temperatures, it is imperative to be aware of the temperature range at which your meter is rated. Most common NORM survey instruments in the oil and gas industry are rated to be used at the standard temperature range of -20 to 50 °C (-4 to 122 °F), and may be certified for operation from -40 to 65 °C (-40 to 150 °F). Meters also have a maximum relative humidity of less then 95% (non-condensing). When using meters in situations that test their proper operating ranges, such as in -10 °F winter weather in North Dakota, or inside a vessel in 115 °F summer weather in West Texas, the surveyor must consider the accuracy of the meter within the strained environment. Extreme temperatures can cause the meter to provide inconsistent readings, registering considerably lower than it if read in the same configuration within the rated temperature range. Measuring the same equipment at a facility within the operating temperature range and outside of said range can produce drastically different results. If lower than expected readings are detected, ensure you also have strong battery power.