How we make this list: we compare pricing pages, product documentation and public user reviews. Ratings come from G2, Capterra or Trustpilot, with the date we checked them.
Key takeaways
- The best free weather API for mobile apps without key in 2026 is led by Open-Meteo, the National Weather Service, and Met Norway for keyless forecasts.
- Keyless APIs need no signup, no API key, and no billing, which suits indie apps, prototypes, and open source projects.
- Keyless does not mean unlimited, since most keyless APIs ask for a proper User-Agent, fair use limits, caching, and polite request rates.
- Open-Meteo suits global forecasts, the National Weather Service suits US forecasts and alerts, and Met Norway suits global forecasts with a strong model.
- Always cache responses and handle failures gracefully, since a free API can slow down or change terms without notice.
Quick comparison
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The best free weather API for mobile apps without key
Starting priceFree
Free planYes
Open-Meteo is the best fit for global forecasts without a key, offering hourly and daily forecasts, current weather, and archive data for any latitude and longitude, with no signup. Its API covers temperature, wind, precipitation, and many other variables, and its docs are clear for mobile developers. Open-Meteo also offers geocoding, elevation, and marine APIs under the same keyless model.
The limits are alerts and guarantees. Open-Meteo offers no severe weather alerts, its free tier has rate limits, and it carries no uptime guarantee. For a mobile app that needs global forecasts without a key, Open-Meteo is the best choice.
What we like- Global coverage
- No key
- Hourly and daily forecasts
Watch out for- No severe weather alerts
- Rate limits
- No historical UI
Starting priceFree
Free planYes
The National Weather Service API suits US forecasts and alerts, offering official forecasts, hourly data, and severe weather alerts for any US point, with no key. Its data comes from the US government, which makes it authoritative for US weather, and its alerts cover tornadoes, floods, and winter storms. Mobile apps for US users gain forecasts and alerts from one keyless source.
The limits are coverage and style. It covers the US only, it requires a proper User-Agent header, and its API style takes learning for new developers. For a US focused mobile app that needs forecasts plus alerts without a key, the National Weather Service API is the best choice.
What we like- Official US data
- Forecasts plus alerts
- No key
Watch out for- US only
- Needs a User-Agent
- API style takes learning
Starting priceFree
Free planYes
Met Norway Locationforecast is the best fit for global forecasts from a national weather service, offering hourly forecasts for any location worldwide with no key. Its model is well regarded for Europe and global use, and its data includes temperature, wind, precipitation, and symbol codes for weather icons. Met Norway asks for a proper User-Agent and fair use, which suits most mobile apps.
The limits are User-Agent rules and docs. It requires a proper User-Agent that identifies your app, its fair use limits cap request rates, and its docs take learning. For a mobile app that wants a trusted global forecast without a key, Met Norway is a strong choice.
What we like- Global coverage
- Strong model
- No key
Watch out for- Needs a User-Agent
- Fair use limits
- Docs take learning
Starting priceFree
Free planYes
7Timer suits astronomical forecasts, offering cloud cover, seeing, transparency, and temperature data for stargazing and outdoor planning, with no key. Its simple API returns data in JSON or XML for any location, and its astro focus suits apps for astronomers, photographers, and outdoor users.
The limits are variables and docs. It covers fewer variables than Open-Meteo, its docs feel older, and it offers no severe weather alerts. For a mobile app focused on skies and stargazing, 7Timer is a strong choice.
What we like- No key
- Astro focused data
- Simple API
Watch out for- Limited variables
- Older docs
- No alerts
Starting priceFree
Free planYes
wttr.in is the best fit for quick weather checks, offering instant JSON weather for any city or coordinate with no key and no signup. Its simplicity makes it ideal for prototypes, demos, and testing, since a single URL returns current weather and a short forecast. Developers often use wttr.in to test a weather UI before wiring a production API.
The limits are production use and depth. It is not built for production apps, its rate limits are strict, and its variables are limited. For a prototype or a quick demo, wttr.in is a strong choice, but production apps should use Open-Meteo or Met Norway instead.
What we like- No key
- Instant JSON
- Simple to test
Watch out for- Not built for production apps
- Rate limits
- Limited variables
Starting priceFree
Free planYes
Bright Sky suits German weather data, offering forecast and historical data from the German Weather Service (DWD) with no key. Its API covers stations and gridded forecasts across Germany, and its open source code lets developers run their own instance. For apps focused on Germany, Bright Sky gives official data without signup.
The limits are coverage and docs. It focuses on Germany, its docs are smaller than Open-Meteo, and it offers no global alerts. For a Germany focused mobile app that needs keyless weather data, Bright Sky is a strong choice.
What we like- No key
- German DWD data
- Historical and forecast
Watch out for- Germany focused
- Smaller docs
- No global alerts
Starting priceFree
Free planYes
Meteostat is the best fit for historical station data, offering daily and hourly observations from weather stations worldwide, with a free API for point data. Its station data suits apps that show past weather, climate trends, or travel history, and its docs cover stations, nearby lookup, and time series.
The limits are forecasts and bulk use. Meteostat focuses on observations, not forecasts, and bulk downloads need care with limits. For a mobile app that needs historical weather without a key, Meteostat is a strong choice.
What we like- Historical station data
- Global stations
- Simple API
Watch out for- Point data focus
- Bulk needs care
- No forecasts
Starting priceFree
Free planYes
Sunrise-Sunset suits sun times, offering sunrise, sunset, dawn, dusk, and day length for any location worldwide with no key. Its simple API suits apps that pair weather with daylight info, such as photography, outdoor, and travel apps. Note plainly that Sunrise-Sunset covers sun times only, not forecasts or weather data, so pair it with Open-Meteo or Met Norway for full weather.
The limits are scope. It offers no temperature, wind, or precipitation data, and no alerts. For a mobile app that needs sun times alongside weather, Sunrise-Sunset is a strong companion choice.
What we like- No key
- Sun times worldwide
- Simple API
Watch out for- Sun times only
- No forecasts
- No weather data
How we chose
We ranked services by keyless access, coverage, data quality, limits, docs, and mobile fit, favoring services that work with no signup over services with free tiers that still need a key. We gave extra weight to global coverage and forecast depth, since a mobile app needs forecasts for users anywhere, and to fair use clarity, since an API that bans your app without warning is worse than one with clear limits. We also weighed docs, since a keyless API with poor docs costs developers more time than a paid API with good docs.
Buying guide
Start by naming your coverage and data needs. A global app suits Open-Meteo or Met Norway, a US app suits the National Weather Service plus Open-Meteo, and a Germany app suits Bright Sky. One coverage match beats an API chosen for features alone.
Next, cache aggressively and handle failures. Cache forecasts for an hour or more, since weather changes slowly, and show the last good forecast with a stale note if an API fails. A mobile app that crashes or shows blank weather when an API slows down will lose users fast.
Finally, respect fair use and identify your app. Send a proper User-Agent with your app name and contact, keep request rates low, and avoid polling every minute. Keyless APIs survive because developers use them fairly, and an app that hammers an API risks a ban for all its users.
Also plan an upgrade path before you launch. If your app grows, move to a paid API with guarantees, or self host an open source option like Bright Sky, rather than relying on a free API with no uptime promise. A growth plan protects your users when a free service changes terms or slows down.
Frequently asked questions
Do keyless weather APIs really need no signup?
Yes for the services in this guide, since Open-Meteo, the National Weather Service, Met Norway, 7Timer, wttr.in, Bright Sky, Meteostat, and Sunrise-Sunset all work without an API key. Some ask for a proper User-Agent header, which identifies your app but is not a signup.
Which keyless API is best for a global mobile app?
Open-Meteo is the best global choice, with hourly and daily forecasts for any location and clear docs. Met Norway is a strong second, especially for Europe, and pairing both gives a fallback if one slows down.
Can I use keyless APIs in a production app?
Yes with care, since keyless APIs carry fair use limits and no uptime guarantees. Cache responses, handle failures gracefully, and plan a paid fallback if your app grows large enough to strain a free service.
Why do some keyless APIs ask for a User-Agent?
A User-Agent identifies your app to the API operator, so they can contact you about abuse or changes and can block bad actors without blocking everyone. Send your app name and a contact address in the User-Agent.
Do keyless APIs offer severe weather alerts?
The National Weather Service API offers US alerts, but most keyless global APIs do not offer alerts. If your app needs alerts outside the US, you will need a paid service or a national weather service API for that country.
How often should a mobile app fetch weather?
Fetch once per hour or less for forecasts, since weather changes slowly, and cache the result on device. Frequent polling wastes battery and data and risks hitting fair use limits on keyless APIs.
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Shihab Mia · Founder, Rankite
Shihab has 5+ years in B2B and SaaS SEO. He writes Rankite's software buying guides from pricing pages, documentation and public user reviews. More about Shihab.
Open-Meteo
National Weather Service
Met Norway Locationforecast
7Timer
wttr.in
Bright Sky
Meteostat
Sunrise-Sunset