Chicago is experiencing a noticeable shift in weather today, marked by cooler temperatures and increasing cloud cover. Daytime temperatures are expected to remain in the low 40s°F (around 5°C), a contrast to the recent milder conditions. Throughout the day, residents should anticipate increasing cloudiness, leading to an overcast evening. Nighttime temperatures are predicted to fall into the low 30s°F (approximately 0°C), signaling the arrival of a colder air mass typical for this time of year. These changes are often influenced by cold fronts originating from the Great Lakes region, which bring cooler air and increased cloud cover.