The Tomorrow.io API allows developers to access and integrate powerful, real-time weather intelligence into their applications. Whether you're building a new weather-focused product or enhancing an existing one with environmental data, the API offers a flexible and scalable solution.
Explore the API Documentation
The Tomorrow.io API documentation is your primary reference for understanding available endpoints, parameters, and expected response formats. The documentation includes everything from basic forecasts to advanced capabilities such as air quality, lightning, and pollen.
You’ll find implementation examples, rate limits, and data granularity details, enabling you to build confidently and efficiently.
Available Data: Core and Premium Tiers
The API provides access to both core and premium datasets:
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Core data includes essential parameters such as:
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Temperature
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Precipitation
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Wind speed and direction
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Humidity
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Cloud cover
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Premium data includes:
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Air quality
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Pollen levels
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Lightning and storm insights
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Specialized aviation data
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Road risk and environmental indexes
- Maritime data
- Soil Moisture data
- And more..
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To access premium datasets, please contact our sales team at sales@tomorrow.io.
Rate Limits and Plans
If you're on the free plan, be sure to review the applicable rate limits here. These limits define how frequently you can make API calls and are essential for managing access without interruptions.
API Reset Timing and Timezone Settings
The API limits reset at midnight UTC.
When reviewing your remaining API call limits, ensure your system or application is set to UTC time. Misalignment in timezones can lead to inaccurate assumptions about quota resets and may result in rejected calls if limits appear unexpectedly exhausted.
Tip: Always confirm your timezone setting when debugging rate-limit behaviors.
How API Calls Are Counted
To make the most of your API plan, it's important to understand how usage is calculated. Tomorrow.io defines one API call as follows:
| Request Type | What Counts as One API Call |
|---|---|
| Data Endpoint | One endpoint + one location = one call. For example: /forecast or /realtime for a specific lat/lon returns all relevant time steps for that data type (e.g., 1m, 15m, hourly, daily). |
| Map Tiles | One request for a tile (defined by zoom and x/y coordinates) = one call. Even though tiles visualize data over an area, the request still counts as a single location call. |
| Widgets | Each widget refresh (e.g., every time a forecast updates) = one call. If a widget is embedded and updates every hour, that’s one call per update. |
Note: This model ensures consistency across formats — whether you retrieve structured data, images, or embeddable tools, each counts as a single usage unit. Visit this article to learn more.
For rate limits by plan, please refer to our Plan Types article.
Using the Smart Search and QA Tool
Not sure where to start? Use the AI-powered Smart Search in the documentation to ask natural-language questions like:
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“How do I get a weather forecast for a specific location?”
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“How can I retrieve weather icons?”
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“What are the supported timesteps?”
This feature helps you discover relevant content instantly and improves onboarding speed.
You can also test your queries with the QA tool, which validates the structure and response of your API calls in real time.
Note: You must be logged into your developer account to access these features.
Try the Customized API Assistant
The Tomorrow.io API Assistant can guide you through building queries step-by-step. It’s especially useful for:
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Selecting the appropriate endpoint
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Structuring requests with valid parameters
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Troubleshooting common issues
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Optimizing queries for performance and cost-efficiency
This assistant ensures your integration is both correct and efficient from the start.
Making Your First API Call
To get started:
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Authenticate: Sign up and retrieve your API key from the developer portal.
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Select your endpoint: Choose the weather data you need (e.g.,
forecast,historical,air quality). -
Build your query: Use query parameters to define location, fields, units, and timesteps.
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Send the request: Use your preferred development environment or tool (e.g., Postman, curl) to make the call and analyze the JSON response.
You can also explore the developer portal for quick-start examples and sample code snippets.
Need Help?
If you have additional questions or run into issues, our support team is here to help.
Contact us at support@tomorrow.io for assistance.
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