ESPWeather

Get location forecast data from the API of MET Norway.

Getting Started

platformio.ini

[env:esp32]
platform = espressif32
board = esp32dev
framework = arduino
lib_deps = 
    https://github.com/sebastian-xyz/ESPWeather.git

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About the Reduced FootPrint (RFP) Classes

ESPWeather provides two main class variants for weather data:

• Standard classes: Weather, WeatherData
  These use float arrays for storing weather data and are suitable for most ESP32 applications.

• Reduced FootPrint (RFP) classes: WeatherRFP, WeatherDataRFP
  These are designed for environments with limited memory.

  • Data is stored in int16_t arrays and scaled by a factor (see the ESPWeatherRFPFactor* defines in the code).
  • The RFP classes use the same API as the standard classes, so you can switch between them with minimal code changes.
  • To use the RFP classes, include weather_rfp.hpp instead of the standard headers and replace Weather with `WeatherRFP.
  • Additionally WeatherDataRFP provides int16_6 get_current_raw() and int16_t get_val_at_hour_raw(uint8_t hour) to gain direct access to the stored values

RFP Defines and Default Values:

Define	Default Value	Description
ESPWeatherRFPFactorTemperature	500.0f	Temperature (°C × 500)
ESPWeatherRFPFactorDewPoint	500.0f	Dew point (°C × 500)
ESPWeatherRFPFactorPrecipitation	1000.0f	Precipitation (mm × 1000)
ESPWeatherRFPFactorWindSpeed	100.0f	Wind speed (m/s × 100)
ESPWeatherRFPFactorWindDirection	50.0f	Wind direction (degrees × 100)
ESPWeatherRFPFactorAirPressure	10.0f	Air pressure (hPa × 10)
ESPWeatherRFPFactorCloudiness	100.0f	Cloudiness (% × 100)
ESPWeatherRFPFactorRelativeHumidity	100.0f	Relative humidity (% × 100)

These defines set the scaling factors for each weather parameter, allowing the library to store values as scaled integers and save RAM. For example, a temperature of 23.456°C is stored as 11728 when using a factor of 500.

How to change the scaling factors:
To override any of these default values, simply #define the desired value before including weather_rfp.hpp in your code.
For example:

#define ESPWeatherRFPFactorTemperature 100.0f
#include <weather_rfp.hpp>

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Example sketch:

#include <Arduino.h>
#include <weather.hpp>
#include <WiFi.h>

Weather *weather_status;

void setup() {

  Serial.begin();

  // get connected
  ...

  // get local time set
  struct tm local;
  configTzTime(TIMEZONE, "pool.ntp.org");
  getLocalTime(&local, 10000);

  weather_status = new Weather(LONGITUDE, LATITUDE, ALTITUDE);
  weather_status->set_utc_offset(1);

  if (WiFi.isConnected()) {
    weather_status->update_data();
  }

}

void loop() {

  if (weather_status->is_expired()) {
    weather_status->update_data();
  }
  Serial.print("Current temperature: ");
  Serial.print(weather_status->get_temperature()->get_current());
  Serial.println("°C);

  Serial.print("Maximum temperature next 24 hours: ");
  Serial.print(weather_status->get_temperature()->get_maximum());
  Serial.println("°C);

  Serial.print("Maximum temperature next 24 hours: ");
  Serial.print(weather_status->get_temperature()->get_minimum());
  Serial.println("°C);

  Serial.print("Mean temperature next 24 hours: ");
  Serial.print(weather_status->get_temperature()->get_mean());
  Serial.println("°C);

}

Available data

Weather Data Stored

Data Type	Unit
Temperature	°C
Precipitation	mm
Dew point	°C
Air pressure	hPa
Wind speed	m/s
Wind direction	deg
Cloudiness	%
Relative humidity	%

Classes - Code Documentation

Weather Class – Public Interface

The Weather class provides an interface to retrieve and manage weather data from the api.met.no weather API.

Public Methods

Return Type	Function	Description
	Weather(float latitude, float longitude)	Constructor to initialize with latitude and longitude.
	Weather(float latitude, float longitude, uint16_t altitude)	Constructor with latitude, longitude, and altitude.
	Weather(uint8_t num_hours, float latitude, float longitude)	Constructor with hours, latitude, longitude.
	Weather(uint8_t num_hours, float latitude, float longitude, uint16_t altitude)	Constructor with hours, latitude, longitude, altitude.
	~Weather()	Destructor.
bool	is_expired(void)	Checks if the weather data is expired.
void	update_data(void)	Updates the weather data from the API.
void	update_location(float latitude, float longitude)	Updates the location (latitude and longitude).
void	update_location(float latitude, float longitude, uint16_t altitude)	Updates the location with latitude, longitude, and altitude.
void	set_utc_offset(int8_t utf_offset)	Sets the UTC offset for the location.
void	set_daylight_saving(bool daylight_saving)	Sets the daylight saving status.
WeatherData*	get_temperature()	Returns a pointer to temperature data.
WeatherData*	get_precipitation()	Returns a pointer to precipitation data.
WeatherData*	get_wind_speeds()	Returns a pointer to wind speed data.
WeatherData*	get_wind_direction()	Returns a pointer to wind direction data.
WeatherData*	get_air_pressure()	Returns a pointer to air pressure data.
WeatherData*	get_cloudiness()	Returns a pointer to cloudiness data.
WeatherData*	get_relative_humidity()	Returns a pointer to relative humidity data.
WeatherData*	get_dew_point()	Returns a pointer to dew point data.
void	setExpiredTime(tm *time)	Sets a pointer to the expiration time structure.
tm*	getExpiredTime()	Returns a pointer to the expiration time structure.
void	set_symbol_code_next_1h(String symbol)	Sets a stored symbol code for the next 1 hour.
void	set_symbol_code_next_6h(String symbol)	Sets a stored symbol code for the next 6 hour.
void	set_symbol_code_next_12h(String symbol)	Sets a stored symbol code for the next 12 hours.
String	get_symbol_code_next_1h()	Returns the symbol code for the next 1 hour.
String	get_symbol_code_next_6h()	Returns the symbol code for the next 6 hours.
String	get_symbol_code_next_12h()	Returns the symbol code for the next 12 hours.

Note:
The Weather class does not expose public data members; all interaction is through its public methods.

WeatherData Class – Public Interface

The WeatherData class represents weather parameter data for a set of hours, providing statistical and value access methods.

Public Methods

Return Type	Function	Description
	WeatherData(uint8_t num_hours)	Constructor that initializes with the number of hours.
	WeatherData(float *vals)	Constructor that initializes with a pointer to values array.
	~WeatherData()	Destructor.
void	update_vals(float *vals)	Updates the internal values array.
void	update_vals(int16_t *vals)	Updates the internal values array.
float	get_minimum()	Returns the minimum value.
float	get_maximum()	Returns the maximum value.
float	get_mean()	Returns the mean value.
float	get_std()	Returns the standard deviation.
float	get_variance()	Returns the variance.
float	get_val_at_hour(uint8_t hour)	Returns the value at the specified hour.
int16_t	get_val_at_hour_raw(uint8_t hour)	Returns the value at the specified hour.
float	get_current()	Returns the value for the current hour.
int16_t	get_current_raw()	Returns the value for the current hour.

Note:
The WeatherData class does not expose public data members; all access is through its public methods.

Debugging Tips

• Enable Debug Output:
  Uncomment or define #define DEBUG_WEATHER at the top of your source files to enable debug print statements throughout the code. This will give you more insight into what your code is doing at runtime.

• Use Serial Monitor:
  Make sure to initialize Serial.begin(115200); in your setup() function. Use Serial.print() and Serial.println() to output variable values and checkpoints.

• Check WiFi Connectivity:
  Ensure the ESP32 is connected to WiFi before making HTTP requests. Print the WiFi status and IP address for confirmation.

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Tip:
If you encounter persistent issues, try running a minimal example sketch that only tests the failing module or function.