west coast usa sleeping bag blah!

[0lski]

I am cycling/camping from Vancouver Sept 12th to San Francisco ,Oct 9th.
I want a light sleeping bag (under 1kg) but I love being roasty-toasty in bed.
Is the 2/3 season rating completely arbitary?
And could anyone suggest a good lightweight option for this time of year and destination.

Thankyou.

[TATANAB]

Lightweight and small pack size - down sleeping bag by RAB. I have a Quantum 400.
http://www.rab.uk.com/products_sleep_qseries.html

[0lski]

Thank's for your advice,Tatanab.