FFXi Weather

This is the website for a one-person FFXi weather collection project that's been ongoing off and on since January 2022. The project aims to archive the retail weather data from packet capture and provide others with a dataset for study and use in their own projects. This project is not affiliated with any other project, group, etc. that may exist.

Prototype FFXi Weather Browser (warning/disclaimer: as this was a personal project originally written in 2022 as a prototype to view the captured data, expect an extremely large download size, a user interface that works best on desktop, and an inaccessible website design. region 41 (aht urhgan) has some display issues but the region is 100% complete.)

The weather browser now has a section, Carby Tracker, for showing the next ten areas for each weather color, to help with the Carbuncle's Ruby / Summoner job unlock quest, "I Can Hear a Rainbow." Same caveats as described above, and times may be off by a minute.

A copy of the dataset can be downloaded from here.

Current Status

Last updated 2026/07/04

Technical Information

A Final Fantasy Xi Vana'diel year is 360 Vana'diel days, a Vana'diel day is 24 Vana'diel hours, a Vana'diel hour is 60 Vana'diel minutes, and a Vana'diel minute is 60 Vana'diel seconds. The FFXi weather system repeats every 6 Vana'diel years. Vana'diel time runs 25 times faster than Earth time. Therefore, a complete cycle of the Vana'diel weather takes 86.4 Earth days. The weather, while originally believed to be randomly generated at runtime, is not actually random at all, and is the same across all servers, meaning that it can be archived perfectly. This also means that anyone attempting to duplicate work already done is just wasting their time and money.

The weather dataset is organized by weather region. Zones that share the same weather pattern are all part of the same weather region.

The downloadable weather dataset contains what has been captured and archived up to this point. zones.json is a mapping between the game's map zone index and weather region id. weather.json is organized by weather region id, and times are stored as Vana'diel minutes. null prev and next values are used to indicate missing data. A table of the client's "w" values are provided below. "t" values are the transition time values used by the game client for weather transition durations.

Weather types

  1. fine (fine patches, as in clear or mostly clear skies)
  2. suny (sunshine, party cloudy)
  3. clod (clouds)
  4. mist (fog)
  5. dryw (hot spells, fire weather)
  6. heat (heat waves, double fire)
  7. rain (rain, water weather)
  8. squl (squalls, double water)
  9. dust (dust storms, earth weather)
  10. sand (sand storms, double earth)
  11. wind (winds, wind weather)
  12. stom (gales, double wind)
  13. snow (snow, ice weather)
  14. bliz (blizzards, double ice)
  15. thdr (thunder, thunder weather)
  16. bolt (thunderstorms, double thunder)
  17. aura (auroras, light weather)
  18. ligt (stellar glare, double light)
  19. fogd (gloom, dark weather)
  20. dark (darkness, double dark)

The Weather Forecaster

Here comes a cool Vana'diel science fact: certain community assumptions[1] about the weather forecaster, while not completely off the mark, did not capture the exact behavior of the forecaster. What the forecaster tells you, for each Vana'diel day, is the main weather, secondary weather, if any, and double weather, if any. Here's how one becomes a certified Vana'diel meteorologist:

  1. Add up the total durations for each weather in a given Vana'diel day. Ignore any amounts that fall outside the current Vana'diel day's 00:00 - 23:59 range.
  2. Find the largest double weather duration. If there is one, and its duration is 60 Vana'diel minutes or more, then that weather is the "slight chance" / "caution is in order" weather.
  3. Now add "fine"'s duration into "suny"'s. Add "mist"'s duration into "clod"'s. Add each double elemental weather duration into its single elemental weather version, and then increase the amount by 25%. Only the elemental weather gets the 25% boost!
  4. Looking at only sunny ("suny"), cloudy ("clod"), and the single elemental weather, find the top two largest durations.
  5. Use the weather with the largest duration as the main weather for the day.
  6. If there is a weather with the second largest duration, then use that as the secondary weather, but only if its duration is 300 Vana'diel minutes or more.
  1. The Yearly Average View in the weather application illustrates the difference between prior assumptions and reality. The top graph is derived from "DSP"/"Topaz" estimates, and the bottom graph is based on retail.↩︎

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR(S) DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

THIS IS AN UNOFFICIAL, INDEPENDENT PROJECT NOT AFFILIATED WITH, ENDORSED BY,
OR APPROVED BY SQUARE ENIX OR ITS AFFILIATES. ALL TRADEMARKS AND GAME CONTENT ARE
PROPERTY OF SQUARE ENIX.

DATA PRESENTED IS DERIVED FROM PACKET CAPTURE ANALYSIS. NO COPYRIGHTED MATERIALS
ARE DISTRIBUTED WITHOUT TRANSFORMATION.

VIEWS EXPRESSED ARE SOLELY THOSE OF THE AUTHOR(S) AND DO NOT REPRESENT
SQUARE ENIX OR ANY OTHER PARTY.