Winter is often more problematic for rosacea and dryness as the air humidity drops outside and central heating inside has two negative effect;

1. It dries out skin more 

2. The more extreme changes in temperature from outdoors and indoors tends to trigger more rosacea flares which in turn results in more dryness. 

An extra layer of hydration  is often required in the winter months to keep roascea prone skin from becoming drier and more itchy.