From 549d448c362e89d5729c6cd479a751d235985374 Mon Sep 17 00:00:00 2001
From: "Adam R. Jensen" <39184289+AdamRJensen@users.noreply.github.com>
Date: Fri, 26 Sep 2025 21:40:36 +0200
Subject: [PATCH] Add note in Hay-Davies model that horizon component is zero

---
 pvlib/irradiance.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pvlib/irradiance.py b/pvlib/irradiance.py
index 5a9051614b..667592834b 100644
--- a/pvlib/irradiance.py
+++ b/pvlib/irradiance.py
@@ -796,7 +796,7 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
             * sky_diffuse: Total sky diffuse
             * isotropic
             * circumsolar
-            * horizon
+            * horizon (always zero, not accounted for by the Hay-Davies model)
 
     Notes
     ------