Sea conditions for IJN carriers during the attack on Pearl Harbour.

[munnst]

Does anyone know how I might determine the colour and sea condition when the IJN carriers launched at the start of the attack on Pearl Harbour?

The carriers were some 200 miles from Pearl.

[S-boat 55]

I've not seen the season state specifically mentioned in anything really, one account I read said the initial wave of 183 aircraft formed up very quickly, in about fifteen mins or so, so you'd expect the weather must have been reasonable, 

[EwenS]

After the ships left Japan on 22nd Nov 1941, they encountered some very heavy seas in what was winter in the North Pacific. It was bad enough that refuelling had to be cancelled on 4th Dec with destroyers rolling up to 45 degrees. However it eased on 5th & 6th allowing completion of all fuelling operations. This was Kaga at one point during the transit.

https://www.history.navy.mil/our-collections/photography/wars-and-events/world-war-ii/pearl-harbor-raid/japanese-forces-in-the-pearl-harbor-attack/miscellaneous-views-of-japanese-forces/NH-75483.html

 

 

By launch time at 0618 on 7th Dec (Hawaii time) the weather had calmed a bit as evidenced by the photos now in the US archives.

https://www.history.navy.mil/our-collections/photography/wars-and-events/world-war-ii/pearl-harbor-raid/japanese-forces-in-the-pearl-harbor-attack/miscellaneous-views-of-japanese-forces.html

 

But note the angle of the deck of Shokaku as the Kate left her deck relative to the horizon. Indicates she was rolling a bit.

 

Fuchida, who led the initial strike later recalled the seas as "rough" an hour or so before launch. There is a report on the weather over Oahu that morning here. IIRC it was cloudy enough to cause the Japanese fliers identifying their targets.

https://www.aos.wisc.edu/~hopkins/Weather_History/Pearl_Harbor/Wx&Pearl_Harbor_weatherwise2007.pdf