diff --git a/esphome/components/bm8563/bm8563.cpp b/esphome/components/bm8563/bm8563.cpp
index 062094c036..d911301c9d 100644
--- a/esphome/components/bm8563/bm8563.cpp
+++ b/esphome/components/bm8563/bm8563.cpp
@@ -63,7 +63,7 @@ void BM8563::read_time() {
            rtc_time.day_of_week, rtc_time.hour, rtc_time.minute, rtc_time.second);
 
   rtc_time.recalc_timestamp_utc(false);
-  if (!rtc_time.is_valid()) {
+  if (!rtc_time.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false)) {
     ESP_LOGE(TAG, "Invalid RTC time, not syncing to system clock.");
     return;
   }
diff --git a/esphome/components/ds1307/ds1307.cpp b/esphome/components/ds1307/ds1307.cpp
index 8fff4213b4..ba2ad6032f 100644
--- a/esphome/components/ds1307/ds1307.cpp
+++ b/esphome/components/ds1307/ds1307.cpp
@@ -44,7 +44,7 @@ void DS1307Component::read_time() {
       .year = uint16_t(ds1307_.reg.year + 10u * ds1307_.reg.year_10 + 2000),
   };
   rtc_time.recalc_timestamp_utc(false);
-  if (!rtc_time.is_valid()) {
+  if (!rtc_time.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false)) {
     ESP_LOGE(TAG, "Invalid RTC time, not syncing to system clock.");
     return;
   }
diff --git a/esphome/components/pcf85063/pcf85063.cpp b/esphome/components/pcf85063/pcf85063.cpp
index 1cf28a4955..000de1433c 100644
--- a/esphome/components/pcf85063/pcf85063.cpp
+++ b/esphome/components/pcf85063/pcf85063.cpp
@@ -44,7 +44,7 @@ void PCF85063Component::read_time() {
       .year = uint16_t(pcf85063_.reg.year + 10u * pcf85063_.reg.year_10 + 2000),
   };
   rtc_time.recalc_timestamp_utc(false);
-  if (!rtc_time.is_valid()) {
+  if (!rtc_time.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false)) {
     ESP_LOGE(TAG, "Invalid RTC time, not syncing to system clock.");
     return;
   }
diff --git a/esphome/components/pcf8563/pcf8563.cpp b/esphome/components/pcf8563/pcf8563.cpp
index b748f0156a..50003ca378 100644
--- a/esphome/components/pcf8563/pcf8563.cpp
+++ b/esphome/components/pcf8563/pcf8563.cpp
@@ -44,7 +44,7 @@ void PCF8563Component::read_time() {
       .year = uint16_t(pcf8563_.reg.year + 10u * pcf8563_.reg.year_10 + 2000),
   };
   rtc_time.recalc_timestamp_utc(false);
-  if (!rtc_time.is_valid()) {
+  if (!rtc_time.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false)) {
     ESP_LOGE(TAG, "Invalid RTC time, not syncing to system clock.");
     return;
   }
diff --git a/esphome/components/rx8130/rx8130.cpp b/esphome/components/rx8130/rx8130.cpp
index 3b704d2551..0aa6e86d31 100644
--- a/esphome/components/rx8130/rx8130.cpp
+++ b/esphome/components/rx8130/rx8130.cpp
@@ -81,7 +81,7 @@ void RX8130Component::read_time() {
       .year = static_cast<uint16_t>(bcd2dec(date[6]) + 2000),
   };
   rtc_time.recalc_timestamp_utc(false);
-  if (!rtc_time.is_valid()) {
+  if (!rtc_time.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false)) {
     ESP_LOGE(TAG, "Invalid RTC time, not syncing to system clock.");
     return;
   }
diff --git a/esphome/core/time.h b/esphome/core/time.h
index ed47432038..0b67b7b3fc 100644
--- a/esphome/core/time.h
+++ b/esphome/core/time.h
@@ -76,8 +76,12 @@ struct ESPTime {
   /// @copydoc strftime(const std::string &format)
   std::string strftime(const char *format);
 
-  /// Check if this ESPTime is valid (all fields in range and year is greater than or equal to 2019)
-  bool is_valid() const { return this->year >= 2019 && this->fields_in_range(); }
+  /// Check if this ESPTime is valid (year >= 2019 and the requested fields are in range).
+  /// @param check_day_of_week validate day_of_week (not always available when constructing from date/time fields)
+  /// @param check_day_of_year validate day_of_year (not always available when constructing from date/time fields)
+  bool is_valid(bool check_day_of_week = true, bool check_day_of_year = true) const {
+    return this->year >= 2019 && this->fields_in_range(check_day_of_week, check_day_of_year);
+  }
 
   /// Check if time fields are in range.
   /// @param check_day_of_week validate day_of_week (not always available when constructing from date/time fields)
diff --git a/tests/components/time/is_valid.cpp b/tests/components/time/is_valid.cpp
new file mode 100644
index 0000000000..9148c0e8d6
--- /dev/null
+++ b/tests/components/time/is_valid.cpp
@@ -0,0 +1,72 @@
+// Regression tests for ESPTime::is_valid() optional checks.
+//
+// The RTC components (ds1307, bm8563, pcf85063, pcf8563, rx8130) read date/time
+// fields from hardware but do not populate day_of_year. They call
+// recalc_timestamp_utc(false) -- which skips day_of_year -- and then is_valid().
+// These tests ensure the is_valid() overload can skip day_of_year validation so
+// RTCs don't log "Invalid RTC time, not syncing to system clock." for valid times.
+
+#include <gtest/gtest.h>
+#include "esphome/core/time.h"
+
+namespace esphome::testing {
+
+// Build an ESPTime that mirrors what the RTC components construct: all fields
+// populated from hardware except day_of_year (left zero-initialized).
+static ESPTime make_rtc_like_time() {
+  ESPTime t{};
+  t.second = 30;
+  t.minute = 15;
+  t.hour = 12;
+  t.day_of_week = 4;  // thursday
+  t.day_of_month = 15;
+  t.month = 4;
+  t.year = 2026;
+  // day_of_year intentionally left at 0 -- RTCs don't compute it.
+  return t;
+}
+
+TEST(ESPTimeIsValid, DefaultRejectsZeroDayOfYear) {
+  // Default is_valid() checks day_of_year; zero-init is out of range.
+  ESPTime t = make_rtc_like_time();
+  EXPECT_FALSE(t.is_valid());
+}
+
+TEST(ESPTimeIsValid, SkipDayOfYearAcceptsRTCLikeTime) {
+  // RTC code path: skip day_of_year validation.
+  ESPTime t = make_rtc_like_time();
+  EXPECT_TRUE(t.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false));
+}
+
+TEST(ESPTimeIsValid, SkipDayOfYearStillRejectsOutOfRangeFields) {
+  ESPTime t = make_rtc_like_time();
+  t.hour = 25;
+  EXPECT_FALSE(t.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false));
+}
+
+TEST(ESPTimeIsValid, SkipDayOfYearStillRejectsYearBefore2019) {
+  ESPTime t = make_rtc_like_time();
+  t.year = 2000;
+  EXPECT_FALSE(t.is_valid(/*check_day_of_week=*/true, /*check_day_of_year=*/false));
+}
+
+TEST(ESPTimeIsValid, SkipBothDayChecksAcceptsGPSLikeTime) {
+  // GPS path (gps_time.cpp) populates neither day_of_week nor day_of_year.
+  ESPTime t{};
+  t.second = 30;
+  t.minute = 15;
+  t.hour = 12;
+  t.day_of_month = 15;
+  t.month = 4;
+  t.year = 2026;
+  EXPECT_TRUE(t.is_valid(/*check_day_of_week=*/false, /*check_day_of_year=*/false));
+  EXPECT_FALSE(t.is_valid());  // default still rejects
+}
+
+TEST(ESPTimeIsValid, FullyPopulatedAcceptsWithDefaults) {
+  ESPTime t = make_rtc_like_time();
+  t.day_of_year = 105;
+  EXPECT_TRUE(t.is_valid());
+}
+
+}  // namespace esphome::testing