diff --git a/Mf2/Parser.php b/Mf2/Parser.php
index 5832191..340043e 100644
--- a/Mf2/Parser.php
+++ b/Mf2/Parser.php
@@ -845,11 +845,12 @@ public function parseDT(\DOMElement $dt, &$dates = array(), &$impliedTimezone =
 				$dtValue = $this->textContent($dt);
 			}
 
-			// if the dtValue is not just YYYY-MM-DD, normalize the timezone offset
+			// if the dtValue is not just YYYY-MM-DD
 			if (!preg_match('/^(\d{4}-\d{2}-\d{2})$/', $dtValue)) {
-				$timezoneOffset = normalizeTimezoneOffset($dtValue);
-				if (!$impliedTimezone && $timezoneOffset) {
-					$impliedTimezone = $timezoneOffset;
+				// no implied timezone set and dtValue has a TZ offset, use un-normalized TZ offset
+				preg_match('/Z|[+-]\d{1,2}:?(\d{2})?$/i', $dtValue, $matches);
+				if (!$impliedTimezone && !empty($matches[0])) {
+					$impliedTimezone = $matches[0];
 				}
 			}
 
@@ -1031,7 +1032,7 @@ public function parseH(\DOMElement $e, $is_backcompat = false, $has_nested_mf =
 		foreach ($temp_dates as $propName => $data) {
 			foreach ( $data as $dtValue ) {
 				// var_dump(preg_match('/[+-]\d{2}(\d{2})?$/i', $dtValue));
-				if ( $impliedTimezone && preg_match('/[+-]\d{2}(\d{2})?$/i', $dtValue, $matches) == 0 ) {
+				if ( $impliedTimezone && preg_match('/[+-]\d{2}:?(\d{2})?$/i', $dtValue, $matches) == 0 ) {
 					$dtValue .= $impliedTimezone;
 				}
 
diff --git a/tests/Mf2/ParseDTTest.php b/tests/Mf2/ParseDTTest.php
index 7f7a78d..2822191 100644
--- a/tests/Mf2/ParseDTTest.php
+++ b/tests/Mf2/ParseDTTest.php
@@ -469,5 +469,16 @@ public function testDtVCPMultipleDatesAndTimezones() {
 		$this->assertEquals('2014-06-01 19:30-0600', $output['items'][0]['properties']['end'][0]);
 	}
 
+	/**
+	 * @see https://github.com/indieweb/php-mf2/issues/149
+	 */
+	public function testDtWithoutYear() {
+		$input = '<div class="h-card"> <time class="dt-bday" datetime="--12-28"></time> </div>';
+		$parser = new Parser($input);
+		$output = $parser->parse();
+
+		$this->assertEquals('--12-28', $output['items'][0]['properties']['bday'][0]);
+	}
+
 }