# Natur Growing Degree Days Calculator

> Natur Growing Degree Days Calculator is a paid API for AI agents from natur.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Accumulates growing degree days (GDD) at a geographic location from hourly forecast data using both hourly integration and the conventional daily max/min average methods, with the difference between them stated.

## Facts

- Endpoint: POST https://natur.halowerk.com/v1/growing-degree-days
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/natur-growing-degree-days-calculator-47ada80a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LRA-PRKb_8bVXHvF3duJf

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability natur-growing-degree-days-calculator-47ada80a -d '<json body>'
```

Example prompt: Calculate growing degree days at latitude 41.85, longitude -88.00 using a base temperature of 10°C, and show me both the hourly integration result and the conventional daily max/min average so I can compare them against the corn growth tables I'm working with.

## When to prefer this

Choose this endpoint when you need GDD accumulation for agronomic decision-making and want both high-accuracy (hourly) and literature-comparable (daily average) results side by side. It is especially valuable when reconciling field observations with published crop or pest threshold tables, since most agronomic references use the daily max/min convention while finer modeling benefits from hourly integration. Prefer this over generic weather APIs that don't compute thermal accumulation directly.

## Known failure modes

- Invalid or out-of-range coordinates return an error
- Unsupported base temperature values may be rejected
- Forecast data unavailable for remote or offshore locations
- Network timeout if weather forecast data retrieval fails
- Malformed request body returns validation error

## How this service works

Accumulates growing degree days at a location from the hourly forecast, for a base temperature you choose. Two methods are returned side by side: the hourly integration, which is the more accurate, and the conventional average of daily maximum and minimum, which is what agronomic tables and most published thresholds are built on. Reporting only one would either be less accurate or incomparable with the literature, so both are given with the difference between them stated.

## Output

Returns two GDD accumulation totals for the requested location and base temperature: (1) the hourly integration method (more accurate, derived from hourly forecast data) and (2) the conventional daily max/min average method (matching agronomic tables and published thresholds), plus the numeric difference between the two values.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "lat": {
   "type": "number",
   "maximum": 90,
   "minimum": -90
  },
  "lon": {
   "type": "number",
   "maximum": 180,
   "minimum": -180
  },
  "thresholds": {
   "type": "array",
   "items": {
    "type": "number",
    "maximum": 5000,
    "minimum": 1
   },
   "maxItems": 6,
   "description": "Accumulated GDD values whose reaching date you want."
  },
  "base_temp_c": {
   "type": "number",
   "default": 10,
   "maximum": 25,
   "minimum": -5,
   "description": "Base temperature. 10 °C is common for maize, 5 °C for cereals."
  },
  "upper_cutoff_c": {
   "type": "number",
   "maximum": 45,
   "minimum": 15,
   "description": "Optional upper limit above which extra heat does not count."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/natur-growing-degree-days-calculator-47ada80a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from natur.halowerk.com](https://www.zero.xyz/host/natur.halowerk.com/llms.txt)