Frequently Asked Questions

General overview

About the company: what is OpenWeather?

OpenWeather (headquartered in London) is a team of IT-intellectuals that create pivotal products for business using climate data. For each point on the globe, OpenWeather provides hyperlocal minutely forecast, historical data, current state, and from short-term to annual forecasted weather data. All data is available via industry standard APIs.

OpenWeather Ltd. has more than 5 million users including Fortune 500 companies and thousands of other businesses globally.

How accurate is OpenWeather?

OpenWeather hyperlocal ML-powered weather model inaccuracy is less than 1% (it is a % of the time when the model was >5°C of ground truth, lower is better).
You can find out more about the OpenWeather model here.

Is OpenWeather API free?

We offer a Free rate that grants access to a variety of data types, including current weather, forecasts, and weather maps, etc. Upon registration on our website using just your email (no banking details required), you will receive an API key that allows for 60 free calls per minute.

Additionally, you can access our One Call API 3.0, which offers an extended data collection. This includes the current weather, a range of forecasts from minute-by-minute predictions for the upcoming hour to long-term forecasts spanning 1.5 years, a historical archive going back over 40 years and many more. With a subscription to One Call API 3.0, you only pay for the number of API calls made to this product, and you receive 1,000 API calls per day for free.

Which weather data OpenWeather provide?

OpenWeather provides forecasts, curent weather and historical data for 43 + years back. Forecasts have different granularity and horizon - from minute by minute, hourly and daily forecasts from . Amongst our products are: One Call API 3.0, Solar Irradiance & Energy Prediction service, Road Risk API, Air Pollution API and solutions for advanced weather parameters like solar irradiance data, UVI, dew point, government weather alerts, etc. Please review our product list page and find more info in the product documentation.

Where does OpenWeather get data from?

To offer global coverage and account for local nuances of climate, OpenWeather hyperlocal ML-powered weather model processes a number of datasets of different granularity, such as local and global models from national agencies such as NOAA and MetOffice, and enhances its model with data from radars, weather stations and satellites.
You can find out more about the OpenWeather model here.

Get started

How to get an API key

In order to use our services, you need to get and use your personal API key in all your API requests. How to do it:

  1. Sign up and get an API key (APPID) on your account page.
  2. Verify your email address via a confirmation letter that will be sent to you. 1 hour after registering, it is possible to resend the confirmation yourself in the profile settings.
  3. After verification, check your Inbox again to find our welcome email that contains your API key and important information.

Congratulations! Now you have a Free OpenWeather account and can start using our services. We highly recommend you to read the API documentation that explains how to use our APIs.

What products and types of data can I request?

For each point on the globe, OpenWeather provides hyperlocal minutely forecast, historical data, current state, and from short-term to annual and forecasted weather data. All data is available via industry standard APIs.

One Call API by call:

Make just one API call and get all your essential weather data for a specific location with One Call API 3.0.

  • Current weather
  • Minute forecast for 1 hour
  • Hourly forecast for 48 hours
  • Daily forecast for 8 days
  • National weather alerts
  • Weather data for 40+ years history archive and 4 days ahead forecast by timestamp
  • Daily aggregated weather data for 40+ years historical archive and 1,5 year forecast ahead

For more functionality, please consider our generous professional subscriptions.

Professional collections:

Current Weather and Forecasts Collection

How to get:

  • APIs (you can request data for geographic coordinates, ZIP codes, city name, city ID, number of cities)
  • Bulk Download (download already collected and regularly updated data for a list of global locations; available for premium subscriptions)

Historical Weather Collection

How to get:

  • On-the-fly bulks for customised lists of coordinates
  • Marketplace of prepared data sets (coordinates, cities, zip codes) - History Bulk (40+ years back), History Forecast Bulk (from 7 Oct 2017)
  • APIs to a timestamp / a period (subscriptions with different limits on calls and depth of archive)

Specialised products:

Detailed information about all our products can be found on the Pricing page.

Do I need to activate my API key?

Your API key will be activated automatically, up to 2 hours after your successful registration. We invite you to read the API documentation that explains how to use our APIs.

How can I use an API key in API calls?

To authorise a request from you and process it, we require you to use your unique API key in each API call.

In order to do this, add your API key as an appid parameter to the GET request, like in the following example:

Just use your API key instead of “YOUR_API_KEY” with your personal API key, it can be found in your personal account on the “API keys” page. You can also create additional API keys there.

Where can I find my API key(s) and generate additional ones?

Your API key can be found in your personal account on the “API keys” page. You can always create additional API keys there.

How many keys can I create?

You can create as many keys as you like. The total number of API calls for your account is counted based on all of your API keys together - please note this when choosing a subscription as they have various limits on API calls that can be made per day/per minute.

How to delete an API key?

You can delete unnecessary API keys but please note that your account with us should have at least 1 API key at any time.

To find your API key, go to your personal account and click the “API keys” tab

When you have more than 1 registered API key, there will be an option to delete an API key.

How often is the weather data updated?

Our Open Weather model is updated every 10 minutes and provides data on all essential weather parameters such as temperature, precipitation, wind, pressure and others. You can find out more about the OpenWeather model here.


Can I use OpenWeather’s APIs commercially?

Yes, you can. Please see our pricing page for more details.

How to ensure that I give the attribution to OpenWeather correctly?

For the plans between Free and Professional, the attribution requirement is obligatory. When it is required by your license you should place the following information in the visible part of your solution:

If you have any doubts about your specific scenario, please reach out to our support team and we will be glad to advise.


What models do you use?

We provide data for any coordinates by utilising our proprietary OpenWeather Weather model. OpenWeather’s advanced ML-based numerical weather model performs at up to 500 m resolution and allows its users to consider highly local nuances of climate and build accurate, efficient products. The model uses a number of data sources - radars, models from global meteorological agencies (e.g., Met Office, NOAA, ECMWF), weather satellites, and a vast network of weather stations. You can find out more about OpenWeather model here.

I have a weather station. Can I connect my station with your system?

If you also believe in the significance of climate data in tackling climate and healthcare challenges and would like to contribute to our initiatives, then we invite you to connect your automated weather station to our platform. The accuracy of weather data benefits from enthusiasts from all over the world and we reward these contributions with our Startup plan.

To contribure your data to our system, please use the Weather station API. To get access to the Startup plan, please contact us.


What are the minimum/maximum temperature fields in the Current Weather API and Forecast Weather API?

In the Current Weather API and Hourly Forecast API:

As it is a current weather data that reflect weather conditions only for the current moment, we add optional statistical parameters the temp_min and temp_max fields to show dispersion of temperature at this current moment. This is the minimum/maximum currently observed temperature or forecast temperature (within large megalopolises and urban areas).

In the 16-Day Forecast API and 30-Day Forecast

The list.temp.min and list.temp.max fields are minimum/maximum daily temperature, and show the minimum and maximum temperatures in the day.

Which time format and timezone are used?

OpenWeather uses Unix time and the UTC/GMT time zone for all API calls, including current weather, forecast and historical weather data. The timezone_offset parameter shows the shift in seconds from UTC. In a One Call API response, there is also a timezone parameter that shows the time zone name for the requested location.

Why I do not see some parameters in the API response?

If you do not see some of the parameters in your API response, it means that these weather phenomena just have not happened for the selected location at the time of measurement. Only actually measured or calculated data is displayed in an API response.

What is the format of the API response?

The JSON format is used by default. To get data in the XML or HTML format, just use “xml” or “html” for the mode parameter. The HTML format is available for Current Weather API only. For the One Call API, data is only available in the JSON format. If the mode parameter is omitted, the format is JSON by default.

Examples of API calls:


How can I switch between temperature units in API calls?

Temperature is available in Fahrenheit, Celsius and Kelvin units. Kelvin is used by default, with no need to use the units parameter in API calls.

For temperature in Fahrenheit, use "units=imperial".

For temperature in Celsius, use "units=metric".

You can find examples of API calls in the documentation for the service you are interested in.

A full list of all API parameters, with units, can be found here.

What are the weather condition codes and icons?

A list of weather condition codes with icons (range of thunderstorm, drizzle, rain, snow, clouds, atmosphere including extreme conditions such as tornado or hurricane) can be found here.

You are free to use these icons in your own solutions.

How can I specify locations in API calls?

Requesting API calls by geographical coordinates is the most accurate way to specify any location. If you need to convert city names and zip-codes to geo coordinates and the other way around automatically, please use our Geocoding API.

However, some of our APIs support in-built geocoding, which allows users to call weather data by city name, city ID and Zip-code. If the chosen API supports built-in geocoding, then you will find the "Buil-it geocoding" section in the API documentation.

We support over 200,000 cities worldwide and our data is available for any coordinates around the globe. However, we don't recommend using large locations or countries as it will not be weather data for a large location (aggregated data or averages), but weather data for a central point of the territory.

Where can I find a list of City IDs?

For current and forecast products (Current API, Hourly Forecast API, Daily Forecast for 16 days, Climatic forecast for 30 days, 5 day/3 hour forecast data) can be downloaded here.

Please note that you can also make requests to our APIs by using coordinates, ZIP codes, etc. Please refer to documentation of specific API to see all available options.

How to determine polar day and polar night using sunset and sunrise time?

Polar day and polar night are natural phenomenons which occur when day and night respectively lasts more than 24 hours and observed for the northernmost and southernmost regions of Earth. During polar day and polar night time of sunset and sunrise are coincide.
So, if sunset and sunrise time for specified location are the same:

  • Polar day will be observed for locations in North hemisphere from March till September and for locations in South hemisphere from September till March
  • Polar night will be observed for locations in North hemisphere from September till March and for locations in South hemisphere from March till September

What is OpenWeather tiled map?

Open Weather maps are tile maps. Tile map or tile web map is a map which image consists of put together from a number of smaller images - tiles, that are draw next to each other, without seams, to create one a much larger image.

For convenience it is assumed that at zoom level 0, an entire Mercator projection of the Earth is contained in one tile with a shape of 256x256 pixels. For each further zoom level all tiles of previous zoom level is divided into 4 parts. This leads to the spatial resolution (ground meters per pixel) of each tile roughly doubles and the number of tiles increases by a factor of four. For example, at zoom level 1, the map consists of 4 tiles with a shape of 256x256 pixels, resulting in an image with a total shape of 512x512 pixels. At any given zoom level, a specific tile can be identified by Cartesian coordinates with 0,0 starting in the top left of the map with the X coordinate values increasing from west to east and Y coordinate values increasing from north to south.

You could find more detailed information about tile maps here.

What X, Y tile coordinate numbers are possible for given zoom level in the OpenWeather tiled map?

The following table provides an indication of zoom levels, possible X, Y tile coordinate numbers, the quantity of tiles at each zoom level, and the scale of each level.

Zoom level Possible X, Y tile coordinate number
(only integers are available)
Quantity of tiles Examples of area to represent
0 1 1 whole world
1 0-1 4 one quarter of the world
2 0-3 16 subcontinental area
3 0-7 64 largest country
4 0-15 256 largest country
5 0-31 1024 large African country
6 0-63 4,096 large European country
7 0-127 16,384 small country, US state
8 0-255 65,536 wide area, large metropolitan area
9 0-511 262,144 wide area, metropolitan area

Weather related symbols

Wind cardinal and degree directions correlation

Wind direction is reported as an orientation from where the wind is blowing. The directions of the wind is determined at the geographical system of coordinates and could be represented in degrees and cardinals terms. wind direction in degrees -azimuth degrees, i.e., in a numerical measure that moves around the Rose of the Winds in a clockwise circle from 0 degrees (N) to 360 degrees (N).Wind direction in cardinals - direction based on are the four main compass directions: north, south, east, and west. Relative to north, the directions east, south, and west are at 90 degree intervals in the clockwise direction.
Please find below the table with correlations between cardinal and degree wind directions:

Cardinal Direction Degree Direction
N 348.75-11.25
NNE 11.25-33.75
NE 33.75-56.25
ENE 56.25-78.75
E 78.75-101.25
ESE 101.25-123.75
SE 123.75-146.25
SSE 146.25-168.75
S 168.75-191.25
SSW 191.25-213.75
SW 213.75-236.25
WSW 236.25-258.75
W 258.75-281.25
WNW 281.25-303.75
NW 303.75-326.25
NNW 326.25-348.75
wind cardinal direction

API errors

API calls return an error 401

You can get the error 401 in the following cases:

API calls return an error 404

You can get this error when you specified the wrong city name, ZIP-code or city ID. For your reference, this list contains City name, City ID, Geographical coordinates of the city (lon, lat), Zoom, etc.

You can also get the error 404 if the format of your API request is incorrect. In this case, please review it and check for any mistakes. To see examples of correct API requests, please visit the Documentation of a specific API and read the examples of API calls there.

API calls return an error 429

You will get the error 429 if you are a user of a Free subscription and make more than 60 API calls per minute (surpassing the limit of your subscription).

Please consider upgrading to a subscription plan that meets your needs or reduce the number of API calls in accordance with the limits.

API calls return errors 500, 502, 503 or 504

In case you receive one of the following errors 500, 502, 503 or 504 please contact us for assistance. Please enclose an example of your API request that receives this error into your email to let us analyze it and find a solution for you promptly.

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