The recent drop in temperatures could cause your car windshield to crack. Glass expands and contracts due to temperature so it is important to avoid sudden temperature changes. Never use boiling water to defrost your windshield. Instead, turn on the defroster and let the windshield warm up slowly. However, be careful not to set the defroster too high. Let the windshield warm up gradually so the glass isn't shocked by cold temperatures outside and warm temperatures inside, which can also lead to cracking. According to glassamerica.net, "No matter how durable a windshield is, it is still glass. Just as an ice-cold drinking glass may crack if exposed to hot water, or another heat source, a windshield can crack due to defroster's heat, and this is most likely to occur if the windshield already has cracks. These reasons are why windshield repair is very important before or during freezing weather."
If a rock chips your windshield, be sure to get it repaired. Sudden temperature changes can cause small chips to start to crack which can lead to your entire windshield cracking, causing you to replace the entire windshield. Be proactive and get rock chips repaired as quickly as possible.