NWS heat index
API · /apparenttemp-api
Apparent Temperature API
healthy
4,322 Subscribers
Apparent ("feels-like") temperature maths as an API, computed locally and deterministically from the official meteorological formulas — the three indices a weather app, dashboard or safety tool reports alongside the raw thermometer reading. The heat-index endpoint gives the US National Weather Service heat index from the air temperature and relative humidity using the full Rothfusz regression with its low- and high-humidity adjustments: because high humidity stops sweat evaporating, the body cannot shed heat and it feels far hotter than the thermometer — 90 °F at 70 % humidity feels like about 106 °F — and the result comes with a risk category from caution through danger to extreme danger. The wind-chill endpoint gives the 2001 NWS / Environment Canada wind chill from the temperature and wind speed, the cold-weather counterpart, with the frostbite-time risk band — 0 °F in a 15 mph wind feels like about −19 °F. The humidex endpoint gives Canada's warm-weather index from the temperature and humidity on the same Celsius scale, derived through the water-vapour pressure. Everything is returned in both °F and °C and computed locally and deterministically, so it is instant and private. Ideal for weather and outdoor apps, occupational-safety and sports tools, smart-home and HVAC dashboards, and climate and health utilities. Pure local computation — no key, no third-party service, instant. Human-comfort estimates in shade and light wind. 3 compute endpoints. For dew point and moist-air properties use a psychrometric API; for live conditions a weather API.
api.oanor.com/apparenttemp-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 77 ms
- Server probes · 24h
- Subscribers
- 4,322
- active
- Total calls
- 76
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 7,400 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 7,400 calls/month
- 2 req/sec
- Heat index + wind chill + humidex
- No credit card
Starter
€8.70 /month
- 78,000 calls / month
- 6 requests / second
- Hard cap (429 above quota, no overage)
- 78,000 calls/month
- 6 req/sec
- Official NWS/EC formulas, °F & °C
- Email support
Pro
€29.50 /month
- 318,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- 318,000 calls/month
- 15 req/sec
- Weather-app & dashboard pipelines
- Priority support
Mega
€89.00 /month
- 1,510,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- 1,510,000 calls/month
- 40 req/sec
- Platform scale
- Dedicated SLA
Built by
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Feels-Like Temperature API
Feels-like (apparent) temperature meteorology as an API, computed locally and deterministically. The wind-chill endpoint computes how cold the air feels when wind carries body heat away, using the Environment Canada formula WC = 13.12 + 0.6215·T − 11.37·V^0.16 + 0.3965·T·V^0.16 from the air temperature (°C) and wind speed (km/h), valid at 10 °C or below with wind of at least 4.8 km/h. The heat-index endpoint computes how hot it feels in warm, humid air with the US National Weather Service Rothfusz regression from temperature and relative humidity, since high humidity slows sweat evaporation, with the low-/high-humidity adjustments. The apparent-temperature endpoint computes the Australian Bureau of Meteorology apparent temperature, AT = Ta + 0.33·e − 0.70·ws − 4.00, which combines the warming effect of humidity (through the vapour pressure e) and the cooling effect of wind (ws in m/s) in a single feels-like value. Temperatures are in °C (Fahrenheit also returned), humidity in %, wind in km/h for wind chill and m/s for apparent temperature. Everything is computed locally and deterministically, so it is instant and private. Ideal for weather, outdoor-activity, sports, smart-home and wearable app developers, comfort and safety tools, and meteorology education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is the feels-like temperature calculator; for the occupational WBGT heat-stress index use a WBGT API and for live weather observations a weather data API.
api.oanor.com/feelslike-api
Weather Calculator API
Meteorological formulas as an API — the derived weather figures, computed from your own readings, with no data feed or key needed. The wind-chill endpoint gives the "feels like" cold using the Environment Canada formula in metric (°C, km/h) or the US NWS formula in imperial (°F, mph), and flags when the reading is outside the valid range. The heat-index endpoint gives the apparent temperature from heat and humidity using the NWS Rothfusz regression with the standard low- and high-humidity adjustments. The dew-point endpoint uses the Magnus formula to turn temperature and relative humidity into the dew point, and also returns the vapour pressure and the absolute humidity. The beaufort endpoint maps a wind speed (m/s, km/h, mph or knots) to its Beaufort force and description, or a force back to its speed range. Everything is computed locally and deterministically, so it is instant and private. Ideal for weather apps and dashboards, agriculture and HVAC, marine and aviation, and outdoor and safety tools. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 5 endpoints. This computes weather formulas from your own readings; for live forecasts and observations use a weather data API.
api.oanor.com/weathercalc-api
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Global river-discharge and flood forecasting as an API, powered by the GloFAS (Global Flood Awareness System) model via Open-Meteo. For any coordinate on Earth, get a daily river-discharge forecast of up to 30 days — with the ensemble spread (mean, max and min across forecast members) so you can gauge uncertainty — plus up to 90 days of recent discharge history, and a quick current-situation summary with today's discharge and a 7-day outlook (peak day, max/min and rising/falling/stable trend). Discharge is reported in cubic metres per second. Ideal for flood early-warning and monitoring, insurance and reinsurance risk, agriculture and irrigation planning, hydropower, and environmental research. Data covers modelled rivers worldwide (none over open ocean). Open data via Open-Meteo / GloFAS.
api.oanor.com/flood-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Apparent Temperature API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Apparent Temperature API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Apparent Temperature API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Apparent Temperature API cost?
Apparent Temperature API has a free tier with 100 calls / month. Paid plans start at €8.70 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Apparent Temperature API GDPR-compliant?
All requests to Apparent Temperature API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/apparenttemp-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/apparenttemp-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/apparenttemp-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);import requests
r = requests.get(
"https://api.oanor.com/apparenttemp-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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