diff --git a/devel/spdlog/Makefile b/devel/spdlog/Makefile
index f8e31aba672b..f475fb50775f 100644
--- a/devel/spdlog/Makefile
+++ b/devel/spdlog/Makefile
@@ -1,39 +1,40 @@
 PORTNAME=	spdlog
 DISTVERSIONPREFIX=	v
 DISTVERSION=	1.16.0
+PORTREVISION=	1
 CATEGORIES=	devel
 
 MAINTAINER=	vanilla@FreeBSD.org
 COMMENT=	Super fast C++ logging library
 WWW=		https://github.com/gabime/spdlog
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 LIB_DEPENDS=	libfmt.so:devel/libfmt
 TEST_DEPENDS=	catch2>0:devel/catch2
 
 USES=		cmake:testing compiler:c++14-lang pathfix
 .if make(test)
 USES+=		pkgconfig
 .endif
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	gabime
 
 EXTRACT_AFTER_ARGS=	--exclude ${GH_PROJECT_DEFAULT}-${GH_TAGNAME_EXTRACT}/include/spdlog/fmt/bundled
 
 PLIST_SUB=	SOVERSION="${DISTVERSION}"
 
 CMAKE_TESTING_ON=	SPDLOG_BUILD_TESTS
 
 CMAKE_ON=	SPDLOG_BUILD_SHARED \
 		SPDLOG_FMT_EXTERNAL
 CMAKE_OFF=	SPDLOG_BUILD_BENCH
 
 post-stage:
 # let consumers know that this package was compiled with SPDLOG_FMT_EXTERNAL=yes
 	${ECHO_CMD} '#define SPDLOG_FMT_EXTERNAL' >> ${STAGEDIR}${PREFIX}/include/spdlog/tweakme.h
 
 .include <bsd.port.mk>
diff --git a/devel/spdlog/files/patch-include_spdlog_details_os-inl.h b/devel/spdlog/files/patch-include_spdlog_details_os-inl.h
new file mode 100644
index 000000000000..7a620b04c1c2
--- /dev/null
+++ b/devel/spdlog/files/patch-include_spdlog_details_os-inl.h
@@ -0,0 +1,23 @@
+The calculate_gmt_offset attempt is a botch. It gets localtm passed in from the
+self-test's yesterday, and then calls time() anew to obtain ::gmtime_r() by way of details::os::gmtime(),
+and that cannot possibly work.
+
+https://github.com/gabime/spdlog/issues/3483
+
+Fix: Disable the non-working code and use tm_gmtoff instead.
+
+--- include/spdlog/details/os-inl.h.orig	2025-10-11 12:53:05 UTC
++++ include/spdlog/details/os-inl.h
+@@ -264,11 +264,7 @@ SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm
+     return offset;
+ #else
+ 
+-    #if defined(sun) || defined(__sun) || defined(_AIX) ||                        \
+-        (defined(__NEWLIB__) && !defined(__TM_GMTOFF)) ||                         \
+-        (!defined(__APPLE__) && !defined(_BSD_SOURCE) && !defined(_GNU_SOURCE) && \
+-         (!defined(_POSIX_VERSION) || (_POSIX_VERSION < 202405L)))
+-    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
++    #if 0
+     struct helper {
+         static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(),
+                                              const std::tm &gmtm = details::os::gmtime()) {