WiFi automatically disconnecting at night is a common but frustrating issue with multiple potential causes, ranging from router settings to ISP infrastructure problems. The pattern of nighttime disconnections often points to scheduled maintenance, network congestion, or device-specific configurations rather than random technical failures. Users across different platforms report similar timing patterns (typically between 10 PM and early morning), suggesting systemic factors like ISP throttling, router power-saving modes, or interference from automated household devices.

Key findings from the sources:

• ISP-related issues are frequently cited, including scheduled maintenance, congestion during peak usage hours, and infrastructure limitations that manifest at night ^[1][3][4]
• Router settings may include scheduled WiFi shutdowns, outdated firmware, or QoS (Quality of Service) configurations that prioritize certain traffic at specific times ^[5][9]
• Device-specific problems such as Android WiFi control apps, Windows power management settings, or MIUI battery optimization features can force disconnections ^[6][7]
• Physical factors like loose cables, signal interference from nighttime appliance usage, or modem overheating after prolonged daytime use may also contribute ^[2][8]

Common Causes and Solutions for Nighttime WiFi Disconnections

ISP Infrastructure and Network Management

Internet Service Providers (ISPs) often perform maintenance or implement traffic management policies that disproportionately affect users during late-night hours. Multiple users report consistent disconnection patterns between 10 PM and 2 AM, aligning with common ISP maintenance windows. In the Xfinity Community Forum, users described persistent nighttime disconnects that were only resolved after area-wide maintenance was completed by the provider ^[4]. Similarly, a Reddit thread noted that ISPs may throttle bandwidth or reroute traffic during off-peak hours to optimize infrastructure performance, inadvertently causing drops for some users ^[1].

Key ISP-related factors:

• Scheduled maintenance: Many ISPs perform updates between midnight and 4 AM, which can temporarily disrupt service. Xfinity users reported that technician visits didn’t resolve their issues until broader area maintenance was conducted ^[4]
• Network congestion: Despite being "off-peak," certain ISPs experience congestion when automated backups, updates, or streaming services run overnight. A Tom’s Hardware user noted their speeds dropped to 1 Mbps nightly, suggesting bandwidth prioritization issues ^[3]
• DNS server problems: Some users resolved nighttime disconnects by switching to alternative DNS servers (like Google’s 8.8.8.8), indicating potential issues with default ISP DNS configurations ^[4]
• Infrastructure limitations: Older coaxial cables or fiber nodes may degrade under specific thermal conditions that occur at night, as suggested by technicians in the Xfinity forum ^[4]

To diagnose ISP issues, users should:

1. Check the ISP’s service status page or outage maps during disconnection times
2. Test with a different DNS server (e.g., Cloudflare’s 1.1.1.1)
3. Contact support to ask about known maintenance windows or congestion in their area
4. Request signal level logs from the ISP to identify patterns ^[3][4]

Device and Router Configurations

Many nighttime disconnections stem from settings within routers or individual devices that activate automatically during specific hours. Router firmware may include power-saving features that reduce signal strength or disable WiFi entirely during perceived "inactive" periods. For example, some routers have a "Wireless Schedule" feature that can be accidentally enabled, cutting off WiFi at predetermined times—such as the 10 PM shutdown described in multiple reports ^[9]. Similarly, Android devices may have battery optimization settings that aggressively disconnect WiFi when the phone is idle, as seen in Samsung and Xiaomi devices ^[6][9].

Critical configuration issues to investigate:

• Router schedules: Many modern routers (including those from TP-Link, Netgear, and ASUS) allow WiFi to be turned off on a schedule. This setting is often buried under "Advanced Wireless Settings" or "Parental Controls" ^[9]
• QoS (Quality of Service) rules: Some routers prioritize certain traffic (like VoIP or gaming) during daytime but may deprioritize general WiFi traffic at night, causing disconnections for less critical devices ^[3]
• Firmware bugs: Outdated router firmware can cause instability, particularly with newer devices. A VMedia article emphasized that 30% of intermittent disconnection issues are resolved by firmware updates ^[5]
• Device power management: Windows 11 PCs and Android phones often have aggressive power-saving modes that disable WiFi adapters when the device is idle. Windows users reported fixing disconnections by disabling "Allow the computer to turn off this device to save power" in Device Manager ^[7]
• MIUI/Xiaomi optimizations: Xiaomi’s MIUI software includes a "Battery saver" feature that may disconnect WiFi overnight unless manually disabled. Users found this setting under "Battery & performance" > "App battery saver" ^[9]

Recommended troubleshooting steps:

1. Check router admin panel for any enabled schedules or QoS settings that might limit nighttime usage
2. Update router firmware to the latest version, as manufacturers frequently patch connectivity bugs ^[5][8]
3. Disable power-saving modes on both the router (often labeled "Green Mode" or "Eco Mode") and individual devices
4. Review connected apps on Android devices via Settings > WiFi > WiFi Control to see which apps have permission to manage WiFi connections ^[6]
5. Test with a different device to isolate whether the issue is router-wide or specific to one device ^[7]