Weather API Overview

2025.08.14

Japan Weather Association’s weather API (Weather Data API) is designed to allow developers to access highly accurate weather information for any location on land between 72°N and 57°S latitude (excluding Greenland).
It allows users to retrieve data such as temperature, humidity, precipitation, snowfall, wind direction and speed, and weather conditions in a single request through a user-friendly API. The data is provided in JSON format, making it easy to integrate into various systems.

1. ‘Weather Data API’ Overview

Available Data

• Temperature
• Humidity
• Precipitation
• Snowfall
• Wind direction and speed
• Weather

API Lists

Click on each link to download the specifications.

• Observations
  • Hourly
    Hourly observed weather data from January 2018 to most recent.
  • Daily
    Daily observed weather data from January 2019 to the previous day.
• Forecasts
  • Hourly (72/120 hours)
    Hourly weather forecast data up to 72/120 hours ahead.
  • Daily (10/14 days)
    Daily weather forecast data up to 10/14 days ahead.
  • Weekly (8 weeks)
    Weekly weather forecast data up to 8 weeks ahead.
    Only temperature is included in the response.
• Historical average values
  • Daily
    Average daily temperatures and historical average values (average of 1993-2016)

Additional specifications are also available for download:

• API common specification
• Global Weather Codes

2. API Specifications

• Format: JSON
• Authentication: API key
• Example – Hourly observations
  • Sample request
    Point (lat, lon)
    <endpoint>/v1/ovsmesh/observations/hourly/point/35.68944,139.691670/time/20190101.json
  • Sample response
    

    {
        "metadata": {
            "author": "Japan Weather Association",
            "title": "global_mesh_hourly_observations",
            "detail": "Success",
            "parameter": {
                "point": "35.68944,139.691670",
                "time": "20220331",
                "lang": "en",
                "format": "json"
            },
            "resultset": {
                "count": 24
            }
        },
        "results": {
            "mesh_code": "2170559",
            "local_time": "utc+09:00",
            "elevation": "-6",
            "data": [
                {
                    "time": "2022-03-31T00:00:00+09:00",
                    "temperature": 14.6,
                    "wind_speed": 3.5,
                    "wind_direction_code": 9,
                    "wind_direction": "SSW",
                    "precipitation": 0,
                    "snowfall": 0,
                    "humidity": 89,
                    "weather_code": 1,
                    "weather": "clear"
                }//,{...}
            ]
        }
    }
    

• Example – Daily Forecasts/10 days
  • Sample request
    Point (lat, lon)
    <endpoint>/v1/ovsmesh/forecasts/bp/daily/point/35.68944,139.691670.json
  • Sample response
    

    {
        "metadata": {
            "author": "Japan Weather Association",
            "title": "global_mesh_daily_forecasts",
            "detail": "Success",
            "parameter": {
                "point": "35.68944,139.691670",
                "lang": "en",
                "format": "json"
            },
            "resultset": {
                "count": 10
            }
        },
        "results": {
            "mesh_code": "2170559",
            "reference_time": "2022-05-19T23:21:47Z",
            "initial_date": "2022-05-20",
            "local_time": "utc+09:00",
            "elevation": "-6",
            "data": [
                {
                    "date": "2022-05-20",
                    "max_temperature": 25.9,
                    "ave_temperature": 22,
                    "min_temperature": 17.3,
                    "max_wind_speed": 3.8,
                    "max_wind_direction_code": 9,
                    "max_wind_direction": "SSW",
                    "ave_wind_speed": 1.6,
                    "most_wind_direction_code": 9,
                    "most_wind_direction": "SSW",
                    "precipitation": 0,
                    "snowfall": 0,
                    "ave_humidity": 72.4,
                    "weather_code": 111,
                    "weather": "clear, cloudy later",
                    "probability_precipitation": 20
                }//,{...}
            ]
        }
    }
    

3. Plans

There are three selectable plans. (Click on each link to download the specifications.)

4. Pricing

Please CONTACT US for price details.

While this article mainly introduces the Global Plans, which provide data for Japan and international locations with a 25-km grid resolution, we also offer the Japan Plans that deliver observed and forecast data for the Japan area at a 1‑km grid resolution, updated hourly.

For more information on Weather API, please visit: Weather Data API

5. How to Get Started

1. Fill out the required information in CONTACT US to get in touch with us.
2. Our representative will send you the application form and terms of use.
3. Complete the necessary information on the application form and return it to our representative.
4. Our representative will provide you with the information needed for API access.
5. You can start using our service!

In the event of system malfunction, the recovery status will be announced on the website.

Appendix: Forecast Accuracy

Comparison of Estimates from Observed data and Forecasts from ‘Weather Data API Global’

From April 13th to 19th, 2022, temperatures were generally lower in Northern North America, China, and Eastern Europe, while higher temperatures were observed in Central Asia, India, and other areas.
As of April 6, JWA’s Weather Data API was largely able to predict the temperatures, except for the low temperatures in Eastern Europe. By April 11, forecasts for low temperatures in Eastern Europe and the degree of low temperatures in China were also predicted with greater accuracy.

For more information on Weather API, please visit: Weather Data API
For inquiries: Contact Us