Low-altitude Airspace Weather Data
We offer a lineup of highly accurate meteorological data covering the Japan area and surrounding regions, including South Korea, Taiwan, and parts of China, from the ground up to low-altitude airspace. In addition to aviation weather data, we can provide integrated high-resolution forecasts based on our proprietary analysis, as well as rain cloud radar, visibility, and cloud base predictions. A wide range of data is available to support operational decision-making and risk management.
Dataset
Spatial Resolution
Vertical Resolution
Time Resolution
Update Frequency
Time Range
Wind/Temperature/Precipitation/Low Cloud Cover/Humidity/Dew Point Temperature/Visibility/Ceiling Data
Horizontal: 250 m Coverage: All regions of Japan, Taiwan, South Korea, and parts of China
10 m (up to 4,500 m above ground) ※ precipitation, low cloud cover, and ceiling are measured at ground level only.
10 minutes
Every hour
Up to 15 hours ahead
Atmospheric Pressure/Wind/Precipitation/Relative Humidity/Snow Depth/Snowfall/Sunshine Duration Data
AMeDAS Observation Station Locations
ー
10 minutes
Every 10 minutes
6 hour ago to now
Observation
Airports in Japan
ー
Hour-level data
Every 30 minutes or hourly,with special reports
Observation
Forecast
Airports in Japan
ー
Hour-level data
4 times/1 day,with special reports
Up to 24/30 hours ahead
Tile-Based Data
Horizontal: 250ｍ～5km Coverage: All regions of Japan ※Refer to the supplementary information for details
ー
5min～1hour
5min～1hour ※Refer to the supplementary information for details
48 hour ago to 15 hours ahead
Wind/Geopotential Height/Atmospheric Pressure Data
Minimum: 250 m² Maximum:10-block division covering Japan Coverage: All regions of Japan
10 m (up to 4,500 m above ground)
Observations Only
10 minutes
Observations Only
Wind/Temperature Data
Horizontal: 250ｍ Coverage: All regions of Japan
10 m (up to 500 m above ground)
・0~1hour：10min ・1~18hour：1hour
Every hour
Up to 15 hours ahead
Visibility/Ceiling Data
Horizontal:5km Coverage: All regions of Japan, Taiwan, South Korea, and parts of China
ground
30 minutes
30 minutes
1 hour ago to 24 hours ahead
High-Resolution Weather Forecasting
This API provides mesh-based weather forecasts for specified latitude and longitude points.
Element
Unit
WND
UGRD：U-component of Wind
*The east–west component of the wind. Positive values indicate wind toward the east, while negative values indicate wind toward the west.
m/s
WND
VGRD：V-component of Wind
*The north–south component of the wind. Positive values indicate wind toward the north, while negative values indicate wind toward the south.
m/s
TMP
Temperature
K
APCP
Accumulated Precipitation
mm
LCDC
Low Cloud Cover
%
RH
Relative Humidity
%
DEW
Dew Point Temperature
K
VIS
Visibility
m
CIG
Ceiling
ft
AMeDAS Real-Time Weather Observations
AMeDAS stands for Automated Meteorological Data Acquisition System and is referred to as a Regional Meteorological Observation System. In order to monitor weather conditions in detail over time and across regions, AMeDAS automatically observes precipitation, wind direction and speed, temperature, and humidity. It plays a crucial role in preventing and mitigating weather-related disasters.
Element
Unit
ARPRSS
Air Pressure Air Pressure at Reporting Station
hPa
TEMP
Temperature
℃
PRCRIN
Precipitation
mm
RHUM
Relative Humidity
%
SNWDPT
Snow Depth
cm
SNWFLL
Snowfall
cm
SSPRSS
Sea Surface Pressure
hPa
SUNDUR
Sunshine Duration
hour
WND（10-min average）
Wind Direction and Speed
wind speed：m/s wind dirction：°（True, 0–360°）
METAR (Meteorological Aerodrome Report) and TAF (Terminal Aerodrome Forecast)
The following data from airports in Japan is available through WNI.
Element
Structure
METAR
Observation
METAR ROAH 080130Z 34008KT 8000 -RA FEW020 BKN120 25/21 Q1020 RMK 2CU020 6AC120 A3014
TAF
Forecast
TAF ROAH 252305Z 2600/2706 25010KT 9999 FEW015 SCT030 BKN045 TEMPO 2609/2615 SHRA
Rain Cloud Radar
This is the rain cloud radar for the Japan area. Data can be obtained on a per-tile basis
Time Range
Available Time Intervals
Data Characteristics at Each Time
Tile images are available from 48 hours ago to 15 hours ahead.
（Example: If the current time is 7/20 02:25, available data ranges from 7/18 03:00 to 7/20 17:00.）
・More than 1 hour in the past: hourly ・Within the past 1 hour: every 5 minutes ・Within the next 1 hour: every 5 minutes ・From 1 to 15 hours ahead: hourly
・Up to 30 minutes ahead: 250 m grid, updated every 5 minutes ・Up to 1 hour ahead: 1 km grid, updated every 5 minutes ・Up to 3 hours ahead: 1 km grid, updated every 10 minutes ・Up to 5 hours ahead: 1 km grid, updated every 30 minutes ・Up to 15 hours ahead: 5 km grid, updated every hour
WNI Observation-Based Analysis Data
This API provides real-time analyzed weather forecasts for specified latitude and longitude points.
Element
Unit
WND
UGRD：U-component of Wind
*The east–west component of the wind. Positive values indicate wind toward the east, while negative values indicate wind toward the west.
m/s
WND
VGRD：V-component of Wind
*The north–south component of the wind. Positive values indicate wind toward the north, while negative values indicate wind toward the south.
m/s
HGT
Geopotential Height
gpm
PRES
Pressure
Pa
Pinpoint LFM
This API provides pinpoint weather forecasts for specified latitude and longitude points.
Element
Unit
Wind Direction
16 compass points
Wind Speed
m/s
Temperature
℃
WNI Original VIS/CIG Forecast Data
This API provides mesh-based weather forecasts for latitude and longitude points specified.
Element
Range
VIS
Visibility
Minimum 100 m, Maximum 9,000 m
＊For visibility above 10 km, the value is 18,000
CIG
Ceiling
Minimum 0 m, Maximum 20,000 m