OpenSenseMap — Free Citizen Science Weather Station Data (No Key)

TL;DR

OpenSenseMap is the open data platform for senseBox citizen science weather stations. Thousands of stations worldwide — built by students, hobbyists, and researchers — continuously upload environmental measurements. The API provides access to station metadata, live sensor readings (temperature, humidity, pressure, UV, PM, noise), and time series data. Particularly dense in Europe and Germany where the senseBox educational project originated. No API key needed, JSON format.

Quick start: https://api.opensensemap.org/boxes/57000b8745fd40c8196ad04c?format=json

No API key needed — just make a request!

How to Use This API

1. Get Station Details

https://api.opensensemap.org/boxes/57000b8745fd40c8196ad04c?format=json

2. Find Nearby Stations

https://api.opensensemap.org/boxes?near=52.0,8.0&maxDistance=10000

3. JavaScript — Find Local PM2.5 Stations

fetch('https://api.opensensemap.org/boxes?near=51.5,-0.1&maxDistance=50000')
  .then(r => r.json())
  .then(boxes => {
    boxes.forEach(box => {
      console.log(`${box.name}: ${box.location?.coordinates}`);
      box.sensors?.forEach(s => {
        if (s.title?.includes('PM2.5')) {
          console.log(`  PM2.5: ${s.lastMeasurement?.value} µg/m³`);
        }
      });
    });
  });

4. Python — Get Temperature Readings

import requests

box_id = '57000b8745fd40c8196ad04c'
data = requests.get(
    f'https://api.opensensemap.org/boxes/{box_id}',
    params={'format': 'json'}
).json()

print(f"Station: {data['name']}")
for sensor in data['sensors']:
    if sensor['unit'] == '°C':
        print(f"Temp: {sensor['lastMeasurement']['value']}°C")
    elif sensor['unit'] == '%':
        print(f"Humidity: {sensor['lastMeasurement']['value']}%")

Get station data: https://api.opensensemap.org/boxes/57000b8745fd40c8196ad04c?format=json

Try This URL Now

Frequently Asked Questions

What types of sensors do senseBoxes have?: Common sensors: temperature, humidity, barometric pressure, illuminance, UV index, PM2.5/PM10, noise level, wind speed, soil moisture, and GPS.
How many stations are there?: OpenSenseMap hosts thousands of active stations globally, with the highest concentration in Germany, Austria, and Switzerland due to the senseBox educational program.
Can I get historical time series?: Yes. Use /boxes/{id}/data/{sensorId} with from-date and to-date parameters to retrieve historical readings for a specific sensor.
How do I find specific sensors in a station?: Each station's JSON includes a sensors array with _id, title, unit, sensorType, and lastMeasurement. Use the sensor ID for data queries.
What format does the API return?: Use ?format=json for JSON output. The API also supports GeoJSON format for mapping applications via ?format=geojson.
Is the data free for commercial use?: Yes, OpenSenseMap data is published as open data (ODbL license). Commercial use is permitted with attribution to the community.

API Details

API URL: https://api.opensensemap.org/boxes
Documentation: docs.opensensemap.org
Category: Weather
Authentication: Not Required
Geographic Coverage: Global — concentrated in Europe

What You Can Build

Citizen science dashboard visualizing community weather data on a map
Educational tool showing students how their senseBox compares to others
Urban heat island mapper using temperature readings from dense station clusters
Air quality monitor aggregating PM sensor readings by neighborhood
Weather alert system using hyperlocal readings from nearby citizen stations