7Timer!

Overview

7Timer! is a specialized weather forecasting service designed for non-commercial applications, particularly in astronomy and hobbyist weather observation. It provides global weather prediction data and imagery derived from various numerical weather prediction (NWP) models. The service distinguishes itself by offering all its resources completely free of charge, making it accessible for developers and enthusiasts who need straightforward access to atmospheric data without commercial licensing or subscription models. The API delivers forecast information in multiple formats, including direct image links for visual representation and structured data in JSON or CSV for programmatic consumption.

The primary use case for 7Timer! involves applications requiring specific atmospheric conditions for astronomical viewing, such as cloud cover, seeing conditions, and transparency. Developers can integrate 7Timer!'s data to power custom weather dashboards, mobile applications for stargazing, or automated systems that monitor local weather suitability for observational astronomy. Beyond astronomy, the API supports general hobbyist weather applications that benefit from global forecast data without needing hyper-local, high-resolution commercial weather services. The underlying data is sourced from established meteorological centers, including the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) and other models, which are commonly used in global weather forecasting efforts, as explained by the 7Timer! FAQ.

The developer experience with 7Timer! is characterized by its simplicity. The API operates via direct HTTP requests, returning predefined image files or data payloads based on specified parameters like coordinates and forecast model. While no SDKs are provided, the documentation clearly outlines the required URL parameters for accessing different forecast products. This approach minimizes integration complexity for developers comfortable with basic web requests. The service focuses on delivering core weather parameters relevant to its target audience, such as temperature, precipitation, wind, cloud cover, and specific astronomical seeing conditions. Its free and open nature allows for rapid prototyping and deployment of weather-dependent applications, making it a suitable choice for academic projects, personal tools, and community-driven initiatives.

Compared to commercial weather APIs that offer high-resolution forecasts, historical data, and advanced features like severe weather alerts, 7Timer! maintains a narrower focus. It prioritizes accessibility and ease of use for its specific niche. This makes it less suitable for critical commercial applications or scenarios requiring guaranteed uptime and enterprise-grade support. However, for users whose primary need is reliable global weather prediction for non-commercial, hobbyist, or astronomical purposes, 7Timer! provides a functional and cost-effective solution. Its design philosophy aligns with the principles of open data access, contributing to the broader ecosystem of publicly available meteorological information, which is a recognized component of a healthy internet ecosystem, as highlighted by organizations like the W3C's Web of Data initiative.

Key features

• Global Weather Forecast Data: Access to predicted atmospheric conditions for any global coordinate.
• Multiple Forecast Models: Utilizes various numerical weather prediction models, including GFS (Global Forecast System), to provide diverse forecast perspectives.
• Image-based Forecasts: Offers direct links to visual weather maps and charts, including cloud cover, temperature, and astronomical seeing conditions.
• Data API (JSON/CSV): Provides raw forecast data in structured JSON or CSV formats for programmatic consumption.
• Astronomy-specific Forecasts: Includes specialized parameters relevant to stargazing, such as transparency and seeing conditions.
• Free Access: All API services and data are available without any cost or subscription.
• Direct HTTP API: Simple REST-like interface requiring direct HTTP GET requests with URL parameters.

Pricing

As of 2026-05-28, all services provided by 7Timer! are free to use. There are no paid tiers, subscriptions, or usage-based fees. The platform operates as a free resource for global weather forecasting, particularly for astronomy and hobbyist applications. Users can find more details regarding this policy on the 7Timer! documentation page.

Common integrations

7Timer!'s API is designed for direct integration into custom applications via HTTP requests. Due to its free and open nature, it is commonly integrated into:

• Custom Astronomy Applications: Developers integrate 7Timer! data to display local or remote astronomical seeing conditions, cloud cover, and transparency for stargazing planning.
• Hobbyist Weather Dashboards: Used to populate personalized weather displays or home automation systems with global forecast data.
• Educational Projects: Integrated into academic or student projects requiring real-time weather data for demonstrations or analyses.
• Open-source Weather Tools: Frequently adopted by community-driven weather projects that benefit from free, accessible meteorological data.
• Scripts and Automation: Utilized in simple scripts (Python, Node.js, etc.) to fetch and process weather data for specific locations or events.

Alternatives

• OpenWeatherMap: Offers a wide range of weather data APIs, including current, forecast, and historical data, with free and commercial tiers.
• AccuWeather API: Provides global weather forecasts, historical data, and severe weather alerts with various commercial plans.
• Weatherbit.io: Focuses on current weather, forecasts, and historical data with robust APIs and flexible pricing.
• AerisWeather API: Offers comprehensive weather data, including severe weather, lightning, and tropical storm data, with commercial licenses.
• Tomorrow.io API: Known for hyper-local, minute-by-minute forecasts and advanced weather intelligence for businesses.

Getting started

To get started with 7Timer!, you typically make a direct HTTP GET request to its API endpoint. The following example demonstrates how to fetch a 24-hour forecast from the GFS model for a specific location (e.g., New York City, approximate coordinates 40.71, -74.01) in JSON format. This example uses a Python script with the requests library.

import requests

# Define the base URL for the 7Timer! API
BASE_URL = "http://www.7timer.info/bin/api.pl"

# Define parameters for the request
# loc: longitude,latitude (e.g., -74.01,40.71 for New York City)
# product: forecast model (e.g., 'civillight' for a basic 24-hour forecast)
# output: desired format (e.g., 'json')
params = {
    "lon": "-74.01",
    "lat": "40.71",
    "product": "civillight",
    "output": "json"
}

try:
    # Make the HTTP GET request
    response = requests.get(BASE_URL, params=params)
    response.raise_for_status()  # Raise an exception for HTTP errors

    # Parse the JSON response
    data = response.json()

    # Print some forecast data
    print(f"Weather forecast for longitude {params['lon']}, latitude {params['lat']}:")
    if 'dataseries' in data:
        for entry in data['dataseries']:
            print(f"  Date: {entry['date']}")
            print(f"    Weather: {entry['weather']}")
            print(f"    Temperature: Min {entry['temp2m']['min']}°C, Max {entry['temp2m']['max']}°C")
            print(f"    Wind: {entry['wind10m_max']} m/s")
            print("----------------------")
    else:
        print("No forecast data available.")

except requests.exceptions.HTTPError as http_err:
    print(f"HTTP error occurred: {http_err}")
except requests.exceptions.ConnectionError as conn_err:
    print(f"Connection error occurred: {conn_err}")
except requests.exceptions.Timeout as timeout_err:
    print(f"Timeout error occurred: {timeout_err}")
except requests.exceptions.RequestException as req_err:
    print(f"An unexpected error occurred: {req_err}")
except ValueError:
    print("Error: Could not decode JSON response.")

This script first defines the BASE_URL and request parameters, including longitude, latitude, the desired forecast product (civillight for a basic forecast), and the output format (json). It then uses the requests.get() method to send the request and parses the JSON response. The civillight product provides a simplified daily forecast, suitable for general weather overview. Other products, such as astro, offer more detailed astronomical conditions. Detailed parameter options are available in the 7Timer! API reference.