Weather Data Classes

frads.WeaMetaData

Bases: NamedTuple

Weather related meta data object.

Attributes:

Name	Type	Description
city	str	City.
country	str	Country.
latitude	float	Latitude.
longitude	float	Longitude.
timezone	int	Timezone as standard meridian.
elevation	float	Site elevation (m).

wea_header

wea_header()

Return a .wea format header.

frads.WeaData

Bases: NamedTuple

Weather related data object.

Attributes:

Name	Type	Description
month		Month.
day		Day.
hour		Hour.
minute		Minutes.
second		Seconds.
hours		Times with minutes as fraction.
dni	float	Direct normal irradiance (W/m2) or illuminance (lux).
dhi	float	Diffuse horizontal irradiance (W/m2) or illuminance (lux).
aod	float	Aeroal Optical Depth (default = 0).
cc	float	Cloud cover (default = 0).
year	float	default = 2000.

Weather File Parsing

frads.parse_epw

parse_epw(epw_str)

Parse epw file and return wea header and data.

Parameters:

Name	Type	Description	Default
epw_str	str	String containing epw file.	required

Returns:

Type	Description
tuple	Tuple of meta data and wea data.

frads.parse_wea

parse_wea(wea_str)

Parse a WEA weather file.

Parameters:

Name	Type	Description	Default
wea_str	str	String containing the complete WEA file content.	required

Returns:

Type	Description
tuple[WeaMetaData, list[WeaData]]	A tuple containing: - WeaMetaData: Location and site information - list[WeaData]: List of weather data entries for each time step

Examples:

>>> with open('weather.wea', 'r') as f:
...     content = f.read()
>>> metadata, data = parse_wea(content)
>>> print(f"Location: {metadata.city}")
>>> print(f"Data points: {len(data)}")

Sky Generation

frads.gen_perez_sky

gen_perez_sky(dt, latitude, longitude, timezone, year=None, dirnorm=None, diffhor=None, dirhor=None, dirnorm_illum=None, diffhor_illum=None, solar=False, grefl=None, rotate=None)

Generate a Perez sky model using the gendaylit Radiance command.

Creates a realistic sky luminance distribution based on the Perez all-weather sky model, which accounts for varying sky conditions from clear to overcast.

Parameters:

Name	Type	Description	Default
dt	datetime	Date and time for the sky calculation.	required
latitude	float	Site latitude in degrees (positive North, negative South).	required
longitude	float	Site longitude in degrees (positive East, negative West).	required
timezone	int	Standard meridian for timezone in degrees.	required
year	None | int	Year for the calculation (optional, uses dt.year if None).	None
dirnorm	None | float	Direct normal irradiance in W/m² (optional).	None
diffhor	None | float	Diffuse horizontal irradiance in W/m² (optional).	None
dirhor	None | float	Direct horizontal irradiance in W/m² (optional).	None
dirnorm_illum	None | float	Direct normal illuminance in lux (optional).	None
diffhor_illum	None | float	Diffuse horizontal illuminance in lux (optional).	None
solar	bool	If True, include solar disk in the sky model.	False
grefl	None | float	Ground reflectance (0.0-1.0, default varies by season).	None
rotate	None | float	Sky rotation angle in degrees (optional).	None

Returns:

Name	Type	Description
bytes	bytes	the sky primitive.

frads.genskymtx

genskymtx(data=None, meta=None, wpath=None, onesun=False, header=True, average=False, sun_only=False, sky_only=False, sun_file=None, sun_mods=None, daylight_hours_only=False, sky_color=None, ground_color=None, rotate=None, outform=None, solar_radiance=False, mfactor=1)

Call gendaymtx to generate a sky/sun matrix Write results to out. It takes either a .wea file path or wea data and metadata (defined in frads.types). If both are provided, .wea file path will be used.

Parameters:

Name	Type	Description	Default
data	None | Sequence[WeaData]	A list of WeaData objects.	None
meta	None | WeaMetaData	A WeaMetaData object.	None
wpath	None | str | Path	A .wea file path.	None
onesun	bool	If True, only one sun will be generated.	False
header	bool	If True, a header will be included in the output.	True
average	bool	If True, the output will be averaged.	False
sun_only	bool	If True, only sun will be generated.	False
sky_only	bool	If True, only sky will be generated.	False
sun_file	None | str	A sun file path.	None
sun_mods	None | str	A sun modifier.	None
daylight_hours_only	bool	If True, only daylight hours will be generated.	False
sky_color	None | list[float]	A list of sky color values.	None
ground_color	None | list[float]	A list of ground color values.	None
rotate	None | float	A rotation value.	None
outform	None | str	An output format.	None
solar_radiance	bool	If True, solar radiance will be generated.	False
mfactor	int	An mfactor value.	1

Returns:

Type	Description
bytes	A bytes object containing the output.

Raises:

Type	Description
ValueError	An error occurs if neither a .wea path nor wea data is provided.