diff --git a/Web/Resgrid.Web.Eventing/Dockerfile b/Web/Resgrid.Web.Eventing/Dockerfile
index 504c68591..2a72f7aa0 100644
--- a/Web/Resgrid.Web.Eventing/Dockerfile
+++ b/Web/Resgrid.Web.Eventing/Dockerfile
@@ -26,12 +26,19 @@ WORKDIR "/src/Web/Resgrid.Web.Eventing"
 
 FROM build AS publish
 ARG BUILD_VERSION
+RUN DEBIAN_FRONTEND=noninteractive apt-get update \
+    && apt-get install -y --no-install-recommends tzdata \
+    && rm -rf /var/lib/apt/lists/*
 RUN dotnet publish "Resgrid.Web.Eventing.csproj" -c Release -o /app/publish  -p:Version=${BUILD_VERSION}
 ADD --checksum=sha256:2241be671073520e028b2f12df1e9ef0419014cffb5670b7a80b2080804be17d https://github.com/ufoscout/docker-compose-wait/releases/download/2.12.1/wait /app/publish/wait
 RUN chmod +x /app/publish/wait
 
 FROM base AS final
 WORKDIR /app
+## Copy the IANA timezone database. DHI/distroless bases ship without tzdata,
+## so TimeZoneInfo (and TZConvert) can't resolve any zone -> TimeZoneNotFoundException.
+COPY --from=publish /usr/share/zoneinfo /usr/share/zoneinfo
+ENV TZ=Etc/UTC
 COPY --from=publish /app/publish .
 # docker-compose-wait waits for WAIT_HOSTS, then execs WAIT_COMMAND.
 # These hardened (distroless) images have no shell, so we can't chain with "sh -c".
diff --git a/Web/Resgrid.Web.Mcp/Dockerfile b/Web/Resgrid.Web.Mcp/Dockerfile
index 5900621ac..f05c61446 100644
--- a/Web/Resgrid.Web.Mcp/Dockerfile
+++ b/Web/Resgrid.Web.Mcp/Dockerfile
@@ -37,12 +37,19 @@ WORKDIR "/src/Web/Resgrid.Web.Mcp"
 
 FROM build AS publish
 ARG BUILD_VERSION
+RUN DEBIAN_FRONTEND=noninteractive apt-get update \
+    && apt-get install -y --no-install-recommends tzdata \
+    && rm -rf /var/lib/apt/lists/*
 RUN dotnet publish "Resgrid.Web.Mcp.csproj" -c Release -o /app/publish -p:Version=${BUILD_VERSION}
 ADD --checksum=sha256:2241be671073520e028b2f12df1e9ef0419014cffb5670b7a80b2080804be17d https://github.com/ufoscout/docker-compose-wait/releases/download/2.12.1/wait /app/publish/wait
 RUN chmod +x /app/publish/wait
 
 FROM base AS final
 WORKDIR /app
+## Copy the IANA timezone database. DHI/distroless bases ship without tzdata,
+## so TimeZoneInfo (and TZConvert) can't resolve any zone -> TimeZoneNotFoundException.
+COPY --from=publish /usr/share/zoneinfo /usr/share/zoneinfo
+ENV TZ=Etc/UTC
 COPY --from=publish /app/publish .
 # docker-compose-wait waits for WAIT_HOSTS, then execs WAIT_COMMAND.
 # These hardened (distroless) images have no shell, so we can't chain with "sh -c".
diff --git a/Web/Resgrid.Web.Services/Dockerfile b/Web/Resgrid.Web.Services/Dockerfile
index ef690221d..d5f0540af 100644
--- a/Web/Resgrid.Web.Services/Dockerfile
+++ b/Web/Resgrid.Web.Services/Dockerfile
@@ -37,12 +37,19 @@ WORKDIR "/src/Web/Resgrid.Web.Services"
 
 FROM build AS publish
 ARG BUILD_VERSION
+RUN DEBIAN_FRONTEND=noninteractive apt-get update \
+    && apt-get install -y --no-install-recommends tzdata \
+    && rm -rf /var/lib/apt/lists/*
 RUN dotnet publish "Resgrid.Web.Services.csproj" -c Release -o /app/publish -p:Version=${BUILD_VERSION}
 ADD --checksum=sha256:2241be671073520e028b2f12df1e9ef0419014cffb5670b7a80b2080804be17d https://github.com/ufoscout/docker-compose-wait/releases/download/2.12.1/wait /app/publish/wait
 RUN chmod +x /app/publish/wait
 
 FROM base AS final
 WORKDIR /app
+## Copy the IANA timezone database. DHI/distroless bases ship without tzdata,
+## so TimeZoneInfo (and TZConvert) can't resolve any zone -> TimeZoneNotFoundException.
+COPY --from=publish /usr/share/zoneinfo /usr/share/zoneinfo
+ENV TZ=Etc/UTC
 COPY --from=publish /app/publish .
 # docker-compose-wait waits for WAIT_HOSTS, then execs WAIT_COMMAND.
 # These hardened (distroless) images have no shell, so we can't chain with "sh -c".
diff --git a/Web/Resgrid.Web.Tts/Dockerfile b/Web/Resgrid.Web.Tts/Dockerfile
index f1b3379e8..df1cc7803 100644
--- a/Web/Resgrid.Web.Tts/Dockerfile
+++ b/Web/Resgrid.Web.Tts/Dockerfile
@@ -32,6 +32,7 @@ RUN apt-get update \
 		xz-utils \
 		gzip \
 		passwd \
+		tzdata \
 	&& rm -rf /var/lib/apt/lists/* \
 	&& curl -fsSL --retry 3 --retry-delay 5 "https://johnvansickle.com/ffmpeg/releases/ffmpeg-release-amd64-static.tar.xz" -o /tmp/ffmpeg.tar.xz \
 	&& curl -fsSL "https://johnvansickle.com/ffmpeg/releases/ffmpeg-release-amd64-static.tar.xz.md5" -o /tmp/ffmpeg.tar.xz.md5 \
@@ -95,6 +96,10 @@ COPY --from=publish /usr/local/bin/ffprobe /usr/local/bin/ffprobe
 COPY --from=publish /tmp/ttsdeps/ /usr/local/lib/tts/
 COPY --from=publish /tmp/app-passwd /etc/passwd
 COPY --from=publish /tmp/app-group /etc/group
+## Copy the IANA timezone database. DHI/distroless bases ship without tzdata,
+## so TimeZoneInfo (and TZConvert) can't resolve any zone -> TimeZoneNotFoundException.
+COPY --from=publish /usr/share/zoneinfo /usr/share/zoneinfo
+ENV TZ=Etc/UTC
 COPY --from=publish /app/publish .
 
 ENV LD_LIBRARY_PATH="/usr/local/lib/tts"
diff --git a/Web/Resgrid.Web/Dockerfile b/Web/Resgrid.Web/Dockerfile
index 4716226b5..6c0a853c5 100644
--- a/Web/Resgrid.Web/Dockerfile
+++ b/Web/Resgrid.Web/Dockerfile
@@ -20,6 +20,7 @@ FROM dhi.io/dotnet:9.0.314-sdk-debian13@sha256:a3acd51de0af79878e26292b3053aab51
 #COPY --from=node_base /usr/local/bin /usr/local/bin
 RUN apt-get update
 RUN apt-get install -y ca-certificates curl gnupg
+RUN DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends tzdata
 RUN curl -sL https://deb.nodesource.com/setup_20.x  | bash -
 RUN apt-get -y install nodejs
 ARG BUILD_VERSION
@@ -61,6 +62,10 @@ RUN chmod +x /app/publish/wait
 
 FROM base AS final
 WORKDIR /app
+## Copy the IANA timezone database. DHI/distroless bases ship without tzdata,
+## so TimeZoneInfo (and TZConvert) can't resolve any zone -> TimeZoneNotFoundException.
+COPY --from=publish /usr/share/zoneinfo /usr/share/zoneinfo
+ENV TZ=Etc/UTC
 COPY --from=publish /app/publish .
 # docker-compose-wait waits for WAIT_HOSTS, then execs WAIT_COMMAND.
 # These hardened (distroless) images have no shell, so we can't chain with "sh -c".
diff --git a/Workers/Resgrid.Workers.Console/Dockerfile b/Workers/Resgrid.Workers.Console/Dockerfile
index 433f0ad2f..cea9b7bb0 100644
--- a/Workers/Resgrid.Workers.Console/Dockerfile
+++ b/Workers/Resgrid.Workers.Console/Dockerfile
@@ -57,6 +57,7 @@ RUN apt-get update \
         libxext6 \
         libxrender1 \
         zlib1g \
+        tzdata \
     && wget -q https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6.1-3/wkhtmltox_0.12.6.1-3.bookworm_amd64.deb \
     && dpkg -i wkhtmltox_0.12.6.1-3.bookworm_amd64.deb || apt-get install -fy \
     && rm -f wkhtmltox_0.12.6.1-3.bookworm_amd64.deb \
@@ -73,6 +74,11 @@ COPY --from=publish /tmp/wkdeps/ /usr/local/lib/wkhtmltopdf/
 COPY --from=publish /etc/fonts/ /etc/fonts/
 COPY --from=publish /usr/share/fonts/ /usr/share/fonts/
 
+## Copy the IANA timezone database. DHI/distroless bases ship without tzdata,
+## so TimeZoneInfo (and TZConvert) can't resolve any zone -> TimeZoneNotFoundException.
+COPY --from=publish /usr/share/zoneinfo /usr/share/zoneinfo
+ENV TZ=Etc/UTC
+
 ENV LD_LIBRARY_PATH="/usr/local/lib/wkhtmltopdf"
 
 COPY --from=publish /app/publish .