diff --git a/homeassistant/helpers/llm.py b/homeassistant/helpers/llm.py
index 37233b0d407..31e3c791630 100644
--- a/homeassistant/helpers/llm.py
+++ b/homeassistant/helpers/llm.py
@@ -35,8 +35,8 @@ from .singleton import singleton
 LLM_API_ASSIST = "assist"
 
 BASE_PROMPT = (
-    'Current time is {{ now().strftime("%X") }}. '
-    'Today\'s date is {{ now().strftime("%x") }}.\n'
+    'Current time is {{ now().strftime("%H:%M:%S") }}. '
+    'Today\'s date is {{ now().strftime("%Y-%m-%d") }}.\n'
 )
 
 DEFAULT_INSTRUCTIONS_PROMPT = """You are a voice assistant for Home Assistant.
diff --git a/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr b/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr
index 587586cff17..70db5d11868 100644
--- a/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr
+++ b/tests/components/google_generative_ai_conversation/snapshots/test_conversation.ambr
@@ -30,7 +30,7 @@
         'history': list([
           dict({
             'parts': '''
-              Current time is 05:00:00. Today's date is 05/24/24.
+              Current time is 05:00:00. Today's date is 2024-05-24.
               You are a voice assistant for Home Assistant.
               Answer in plain text. Keep it simple and to the point.
               Only if the user wants to control a device, tell them to edit the AI configuration and allow access to Home Assistant.
@@ -81,7 +81,7 @@
         'history': list([
           dict({
             'parts': '''
-              Current time is 05:00:00. Today's date is 05/24/24.
+              Current time is 05:00:00. Today's date is 2024-05-24.
               You are a voice assistant for Home Assistant.
               Answer in plain text. Keep it simple and to the point.
               Only if the user wants to control a device, tell them to edit the AI configuration and allow access to Home Assistant.
@@ -144,7 +144,7 @@
         'history': list([
           dict({
             'parts': '''
-              Current time is 05:00:00. Today's date is 05/24/24.
+              Current time is 05:00:00. Today's date is 2024-05-24.
               You are a voice assistant for Home Assistant.
               Answer in plain text. Keep it simple and to the point.
               <no_api_prompt>
@@ -199,7 +199,7 @@
         'history': list([
           dict({
             'parts': '''
-              Current time is 05:00:00. Today's date is 05/24/24.
+              Current time is 05:00:00. Today's date is 2024-05-24.
               You are a voice assistant for Home Assistant.
               Answer in plain text. Keep it simple and to the point.
               <no_api_prompt>
@@ -254,7 +254,7 @@
         'history': list([
           dict({
             'parts': '''
-              Current time is 05:00:00. Today's date is 05/24/24.
+              Current time is 05:00:00. Today's date is 2024-05-24.
               You are a voice assistant for Home Assistant.
               Answer in plain text. Keep it simple and to the point.
               <api_prompt>
@@ -309,7 +309,7 @@
         'history': list([
           dict({
             'parts': '''
-              Current time is 05:00:00. Today's date is 05/24/24.
+              Current time is 05:00:00. Today's date is 2024-05-24.
               You are a voice assistant for Home Assistant.
               Answer in plain text. Keep it simple and to the point.
               <api_prompt>