OpenWeather
The developer-default weather API — generous free tier, minutely nowcasts, 40+ years of history, air quality and map layers.
About
OpenWeather (formerly OpenWeatherMap) is the weather API most developers reach for first. Founded in 2012 in London by Denn and Olga Ukolov, the company claims more than six million users and over two billion forecasts served per day, with customers ranging from independent developers to Fortune 500 firms. Google used it for weather-targeted ads in 2015, and Samsung baked it into Galaxy Watch Studio in 2020.
The product range is wide: current weather, 3-hour/5-day and 16/30-day forecasts, the One Call API with minutely precipitation nowcasts, government weather alerts, historical archives back to 1979, air pollution, geocoding, weather map tiles, plus specialist products for solar energy, road risk and agriculture. Access is self-serve with an ongoing free tier (60 calls/minute, a defined monthly allowance, plus a student plan); paid tiers start around $40/month (Startup) with pay-per-call options on One Call 4.0. Some data is published under a CC BY-SA license, which is unusual in this space.
What it can do
- Current weather and 5-day/3-hour forecasts
- One Call API: minutely, hourly and 8-day data
- Historical archives back to 1979
- Air pollution and UV data
- Weather map layers and tiles
- Geocoding API
- Solar, road-risk and agriculture products
Setup
Register at openweathermap.org, copy the API key from the dashboard, and call api.openweathermap.org with lat/lon — no card required for the free tier.
Prerequisites
Free account for the free tier; API key required on all calls.
Use cases
Works with
Trust score — 7/10
Scored 7/10 (TIER metrics, metrics-v1). Evidence: founding (2012, London, Ukolovs), 6M+ users and 2B forecasts/day reported via Wikipedia citations; Google and Samsung integrations documented; pricing tiers corroborated by independent reporting. Strengths: true self-serve, strongest free tier in the category, huge SDK ecosystem, CC BY-SA data access is a rarity. Docked for: (1) accuracy vs ECMWF-heavy rivals is debated and not independently benchmarked; (2) exact free-tier call limits have shifted over time and vary across sources; (3) no published independent forecast-accuracy benchmarks. License: proprietary API; free tier plus paid from ~$40/month; some data CC BY-SA.
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 9.0/10
- Maintenance · recency, releases, issue load
- 8.0/10
- Openness · license + docs
- 5.0/10
- Manual review · sanity read + red-flag check
- 8.0/10
- · Founded 2012 in London by Denn and Olga Ukolov
- · 6M+ users, 2B+ forecasts/day claimed
- · Used by Google (2015 ads) and Samsung Galaxy Watch Studio (2020)
- · Free tier self-serve; One Call pay-per-call; Startup ~$40/mo, Developer ~$160/mo
- · No published independent forecast-accuracy benchmarks
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.