diff --git a/esphome/core/time.cpp b/esphome/core/time.cpp
index 554431c631a..1aea18ac8d3 100644
--- a/esphome/core/time.cpp
+++ b/esphome/core/time.cpp
@@ -8,7 +8,7 @@ namespace esphome {
 
 uint8_t days_in_month(uint8_t month, uint16_t year) {
   static const uint8_t DAYS_IN_MONTH[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
-  if (month == 2 && (year % 4 == 0))
+  if (month == 2 && (year % 4 == 0) && (year % 100 != 0 || year % 400 == 0))
     return 29;
   return DAYS_IN_MONTH[month];
 }
diff --git a/esphome/core/time.h b/esphome/core/time.h
index 87ebb5c2213..d9ce86131c3 100644
--- a/esphome/core/time.h
+++ b/esphome/core/time.h
@@ -70,14 +70,14 @@ 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 2018)
+  /// 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 all time fields of this ESPTime are in range.
   bool fields_in_range() const {
     return this->second < 61 && this->minute < 60 && this->hour < 24 && this->day_of_week > 0 &&
-           this->day_of_week < 8 && this->day_of_month > 0 && this->day_of_month < 32 && this->day_of_year > 0 &&
-           this->day_of_year < 367 && this->month > 0 && this->month < 13;
+           this->day_of_week < 8 && this->day_of_year > 0 && this->day_of_year < 367 && this->month > 0 &&
+           this->month < 13 && this->day_of_month > 0 && this->day_of_month <= days_in_month(this->month, this->year);
   }
 
   /** Convert a string to ESPTime struct as specified by the format argument.