Arrival Heights Automatic Weather Station unmodified monthly observational data, 2005-present (ongoing).

The archive spans January 1, 2005 through the present. Observations prior to January 1, 2026 were collected and archived in several plain-text formats that changed periodically over the archive's history and have been standardized into the single format described here. Observations from January 1, 2026 onward conform to this format natively.

Two standardization steps were applied to the pre-2026 record: atmospheric pressure values originally recorded in millimeters of mercury (mmHg) have been converted to hectopascals using the factor 1 mmHg = 1.33322 hPa, and all timestamps have been normalized to 24-hour format. No observations have been removed or adjusted. The observation interval is variable and is recorded in the final column (Arc.

Int.). The predominant interval is one minute; intervals of five minutes and thirty minutes also appear in the record. File names follow the convention ArrivalHeights.observations.monthly.YYYY.mm.txt, where YYYY is the four-digit year and mm is the two-digit month.

One file is produced per calendar month. Each file contains a two-line header. The first header line gives abbreviated column group labels; the second gives the full column names.

Data rows begin on line three. All fields are tab-delimited. All times are reported in Coordinated Universal Time (UTC).

Atmospheric pressure is reported in hectopascals (hPa). Time is reported in 24-hour format as H:MM without a leading zero on the hour. Dates are formatted as MM/DD/YY.

The columns are organized in the following order: - Date Observation date (MM/DD/YY) - Time Observation time, 24-hour format (H:MM) - Temp Out Outdoor temperature (°C) - Hi Temp Highest temperature in archive interval (°C) - Low Temp Lowest temperature in archive interval (°C) - Out Hum Outdoor relative humidity (%) - Dew Pt. Outdoor dew point temperature (°C) - Wind Speed Average wind speed in archive interval (knots) - Wind Dir Dominant wind direction in archive interval - Wind Run Wind run in archive interval (nautical miles) - Hi Speed Highest wind speed in archive interval (knots) - Hi Dir Wind direction at time of highest speed - Wind Chill Wind chill temperature (°C) - Heat Index Heat index (°C) - THW Index Temperature-Humidity-Wind index (°C) - Bar Barometric pressure, station level (hPa) - Heat D-D Heating degree-days accumulated in archive interval - Cool D-D Cooling degree-days accumulated in archive interval - In Temp Indoor (enclosure) temperature (°C) - In Hum Indoor relative humidity (%) - In Dew Indoor dew point temperature (°C) - In Heat Indoor heat index (°C) - In EMC Indoor equilibrium moisture content (%) - In Air Density Indoor air density (kg/m³) - Wind Samp Number of wind samples in archive interval - Wind Tx Number of wind transmissions received in archive interval - ISS Recept Integrated Sensor Suite reception rate (%) - Arc.

Int. Archive interval (minutes) Not all columns are populated for all dates. Columns absent from the original proprietary format for a given time period are filled with the missing data indicator (---).

Known Measurement and Reporting Changes: The station operator (McMurdo Station) implemented several instrument and reporting changes effective January 1, 2026, coinciding with the station's switch to native monthly reporting. Two of these changes affect the physical basis of archived variables and are not corrected for in this dataset: Bar (barometric pressure): Prior to January 1, 2026, Bar values were corrected from the station's elevation (600 ft / 183 m) to sea level.

From January 1, 2026 onward, the station's elevation setting was changed to zero, so it now reports raw, uncorrected station pressure. Bar values from before and after this date represent different physical quantities and are not directly comparable without an independent elevation correction. In Air Density: Prior to January 1, 2026, this value was computed and reported in pounds per cubic foot (lb/ft³).

From January 1, 2026 onward it is reported in kilograms per cubic meter (kg/m³). This unit change has not been corrected in the pre-2026 archive. Separately, on January 31, 2026 at 23:59 UTC, the station's Paroscientific barometer standard was recalibrated, shifting the reported pressure from 970.7 to 972.9 hPa.

This produces a step change in the Bar record at that timestamp, independent of the elevation-correction change described above.