Venice in the first week of October is often at its most enchanting — warm days, crisp evenings, and fewer crowds. Although it can be variable, expect average daytime temperatures in the low to mid-60s °F (around 16–19°C), with cooler nights that may dip into the low to mid 50s°F (10–12°C).  It will likely feel a little cool for early evening cocktails and the ceremony, so an evening jacket, layers or a shawl will be your best friend.