YOU SAID:
The weather looks dull today
INTO JAPANESE
今日の天気は鈍い
BACK INTO ENGLISH
Today's weather is dull
INTO JAPANESE
今日の天気はつまらない
BACK INTO ENGLISH
The weather today is boring
INTO JAPANESE
今日の天気はつまらない
BACK INTO ENGLISH
The weather today is boring
That didn't even make that much sense in English.