Yep, waiting until the cold has passed will really help. My babies all needed more BFing at night when they had a cold... and it really does help them get over it more quickly. Once the weather warms up a bit I expect my 2yo will sleep through more reliably too. It was 4'C here last night (we don't have the central heating on over night). Teething also plays a part in night wakefulness... oh the joys!!!