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Climatic Data OnLine (CDO)


Global Climate Station Summaries (TD3505)
ISD Summary – Sea-Level Pressure Statistics Help

Purpose: This summary shows means and standard deviations (stdv) of barometric pressure corrected for sea-level at one or more weather station locations. The table also shows the number of weather observations used in the calculation. (#obs). This is based on the number of valid observations available in the ISD database for the chosen location-periods. The summary will differentiate between months of the year and hour of day. Users define the weather station(s) by city and the period of time with which to calculate the statistics.


Units: Sea-Level Pressures are given in hectopascals (HPa). To convert to inches of mercury (in Hg) you must multiply the HPa value by 0.02952465. Hectopascals are numerically equivalent to millibars (mb).


Date Restrictions

Choosing Date Range gives the user the available data over the period of record (e.g. between the selected dates).
Choosing Selected Dates gives the user the available data for the individual dates selected. Summaries will be generated for each year selected.


Time Information: Time ranges in the table are located in the leftmost column and are represented by a number for the hour from 0 to 23 as follows:

  • 0 indicates from midnight through 12:59 am UTC
  • 1 indicates from 1:00 am through 1:59 am UTC
  • 2 indicates from 2:00 am through 2:59 am UTC
  • 3 indicates from 3:00 am through 3:59 am UTC
  • 4 indicates from 4:00 am through 4:59 am UTC
  • 5 indicates from 5:00 am through 5:59 am UTC
  • 6 indicates from 6:00 am through 6:59 am UTC
  • 7 indicates from 7:00 am through 7:59 am UTC
  • 8 indicates from 8:00 am through 8:59 am UTC
  • 9 indicates from 9:00 am through 9:59 am UTC
  • 10 indicates from 10:00 am through 10:59 am UTC
  • 11 indicates from 11:00 am through 11:59 am UTC
  • 12 indicates from 12:00 pm through 12:59 pm UTC
  • 13 indicates from 1:00 pm through 1:59 pm UTC
  • 14 indicates from 2:00 pm through 2:59 pm UTC
  • 15 indicates from 3:00 pm through 3:59 pm UTC
  • 16 indicates from 4:00 pm through 4:59 pm UTC
  • 17 indicates from 5:00 pm through 5:59 pm UTC
  • 18 indicates from 6:00 pm through 6:59 pm UTC
  • 19 indicates from 7:00 pm through 7:59 pm UTC
  • 20 indicates from 8:00 pm through 8:59 pm UTC
  • 21 indicates from 9:00 pm through 9:59 pm UTC
  • 22 indicates from 10:00 pm through 10:59 pm UTC
  • 23 indicates from 11:00 pm through 11:59 pm UTC
  • Total indicates from midnight to 11:59pm UTC

Please note that all times are UTC (Universal Time Coordinate) and must be adjusted for local time if desired.