zambretti-py 0.0.2

The Zambretti Algorithm for weather forecasting

Zambretti Weather Forecasting in Python

This is a Python implementation of the Zambretti Weather Forecaster

The code is heavily based on the Zambretti Algorithm for Weather Forecasting ESP example

Further reading: Short-Range Local Forecasting with a Digital Barograph using an Algorithm based on the Zambretti Forecaster.

Usage notes

Pressure data must be provided in millibars or hPa (those are equivalent). Elevation must be provided in meters. Temperature must be provided in degrees Celsius.

Minimum 6 readings of atmospheric pressure are required. Best results are when the pressure readings span the last three hours, but the code will run on any timespan.

Technical notes

This project has no dependencies, uses only functions from the Python Standard Library. It should run both in Python and MicroPython.

Example

Example usage with mock values:

import datetime

from zambretti_py import PressureData, WindDirection, Zambretti

now = datetime.datetime.now()
pressure_data = PressureData(
    [
        (now - datetime.timedelta(hours=2, minutes=59), 1050.0),
        (now - datetime.timedelta(hours=2, minutes=49), 1040.0),
        (now - datetime.timedelta(hours=2, minutes=39), 1030.0),
        (now - datetime.timedelta(hours=2, minutes=12), 1020.0),
        (now - datetime.timedelta(hours=1, minutes=19), 1010.0),
        (now - datetime.timedelta(minutes=20), 1000.0),
    ]
)
zambretti = Zambretti()

forecast = zambretti.forecast(
    pressure=1013.0,
    elevation=90,
    temperature=25,
    pressure_data=pressure_data,
    wind_direction=WindDirection.NORTH,
)
print(forecast)

To calculate for forecast, the Zambretti algorithm requires:

• elevation above sea level
• current temperature
• pressure data from the last three hours, or less.
  • data points older than three hours will be removed
  • the pressure data is expected to be provided as a list of tuples, each tuple consisting of a datetime.datetime object, and the pressure as float
• optional wind direction, denoting the direction from which the wind is flowing. This has a minor effect on the forecast and can be omitted.

The result will be a text description of the forecasted weather.