This site usually sticks to the traditional 5-7-5. But the modern haiku is less than 17 syllables, and it doesn't matter how many syllables are in each line so long as the haiku has 17 syllables or less, but the author should at least attempt the haiku to look like traditional one even if it doesn't have the 5-7-5 count. Well done.
revealing a frosty dawn:
a blackbird sings
Slight critique first...you have two 'a's here and, for such a short verse it was more noticeable to me.
About the syllable count...this site seems to favour the 5,7,5 which is more common in the western world but, in the Japanese language, where there sounds and characters are different from ours, they will not translate into a count of 5,7,5 when translated into English. Here is a link that may explain it better than I can.
A title that intrigues, not least because it is a haiku, and so I know (from what you have taught me) the content could be about anything that remotely relates! Is it a burglar? Is it a car siren? Is it a fox? (a haunting sound) or is it a lustful missus? lol Well, the list goes on, so I better continue.
This intrigued me because I instantly scanned rather than read the content thinking I'd stumbled on a syllable error! But no; 13 at my count and senryu and haiku should be 17 OR LESS, which not everyone realises. Different, then which makes it more interesting....daring, you might say!
Anyway, "night breaks" - an instant impression of dawn, the sun creeping above the horizon, red skies, birds singing, etc.
"revealing a frosty dawn"
I love those morning, Michael, particularly when walking my dogs (as long as I have my hat). It was at this point, I realised that it is a haiku, so it was going to be about nature, not sirens, foxes, or lusty wives! lol I am slow sometimes.....
"a blackbird sings"
Image complete. The sounds, the feel of the frost underfoot, the cold crisp air, the sunlight through the curtains - whatever takes your fancy, it's all here.
A lovely haiku, Michael and a welcome new post from you - subtle, but subtly forceful, if that makes sense. This has my nomination come Monday.