Wi-Fi signal strength of -128dB being reported since 21 November

ESPHome
1

My greenhouse ESP32-S3 is on a cycle of deep_sleep for 30 minutes, then wake and report sensor values for 3 minutes before going back to sleep. Since the greenhouse is at the back of my property I also monitor the wi-fi connection and LiPo battery voltage.

But since November 21 I have been getting Wi-fi signal strength readings of -128dB.

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I have brought the ESP32 inside to my study and have found that the WiFi component is initialised to -128

[2025-12-07 11:07:23] [C][status:021]:   Device Class: 'connectivity'
[2025-12-07 11:07:23] [C][captive_portal:122]: Captive Portal:
[2025-12-07 11:07:23] [C][wifi:1062]: WiFi:
[2025-12-07 11:07:23]   Connected: NO
[2025-12-07 11:07:23] [C][wifi:827]:   Local MAC: 98:3D:AE:EB:24:F4
[2025-12-07 11:07:23] [C][wifi:834]:   IP Address: 192.168.1.124
[2025-12-07 11:07:23] [C][wifi:838]:   SSID: ''
[2025-12-07 11:07:23]   BSSID: 00:00:00:00:00:00
[2025-12-07 11:07:23]   Hostname: 's3-xxx'
[2025-12-07 11:07:23]   Signal strength: -127 dB ××××
[2025-12-07 11:07:23]   Channel: 4
[2025-12-07 11:07:23]   Subnet: 255.255.255.0
[2025-12-07 11:07:23]   Gateway: 192.168.1.1
[2025-12-07 11:07:23]   DNS1: 0.0.0.0
[2025-12-07 11:07:23]   DNS2: 0.0.0.0
[2025-12-07 11:07:23] [C][web_server:326]: Web Server:
[2025-12-07 11:07:23]   Address: 192.168.1.124:80
[2025-12-07 11:07:23] [C][esphome.ota:093]: Over-The-Air updates:
[2025-12-07 11:07:23]   Address: 192.168.1.124:3232
[2025-12-07 11:07:23]   Version: 2

What I can’t figure is how this -128dB value gets sent to Home Assistant. When the Wi-Fi connects, it measures signal strength

[2025-12-07 11:07:25] [D][main:253]: ########### ON_BOOT continues ###########
[2025-12-07 11:07:25] [D][main:259]: ##### on_boot -100 finished
[2025-12-07 11:07:25] [D][main:262]:  
[2025-12-07 11:07:25] [I][wifi:1079]: Connected
[2025-12-07 11:07:25] [C][wifi:827]:   Local MAC: 98:3D:AE:EB:24:F4
[2025-12-07 11:07:25] [C][wifi:834]:   IP Address: 192.168.1.124
[2025-12-07 11:07:25] [C][wifi:838]:   SSID: 'dagoba'
[2025-12-07 11:07:25]   BSSID: 64:66:B3:ED:08:C4
[2025-12-07 11:07:25]   Hostname: 's3-xxx'
[2025-12-07 11:07:25]   Signal strength: -52 dB ▂▄▆█
[2025-12-07 11:07:25]   Channel: 13
[2025-12-07 11:07:25]   Subnet: 255.255.255.0
[2025-12-07 11:07:25]   Gateway: 192.168.1.1
[2025-12-07 11:07:25]   DNS1: 0.0.0.0
[2025-12-07 11:07:25]   DNS2: 0.0.0.0
[2025-12-07 11:07:25] [D][wifi:1103]: Disabling AP
[2025-12-07 11:07:25] [D][wifi:1649]: Saved fast_connect settings
[2025-12-07 11:07:25] [W][component:337]: wifi cleared Warning flag
[2025-12-07 11:07:26] [D][api:161]: Accept 192.168.1.97
[2025-12-07 11:07:26] [W][component:337]: api cleared Warning flag
[2025-12-07 11:07:26] [D][binary_sensor:041]: 'Status': New state is ON
[2025-12-07 11:07:26] [D][api.connection:1386]: ESPHome Logs 2025.11.4 (192.168.1.97) connected
[2025-12-07 11:07:26] [D][time:068]: Synchronized time: 2025-12-07 11:07:26
[2025-12-07 11:07:26] [I][app:190]: ESPHome version 2025.11.4 compiled on Dec  7 2025, 11:07:02

… and since wi-fi needs to be connected to send the sensor readings to HA, surely it should be sending the actual values ? And of course if I cut out all the logic related to other sensors … the problem goes away.

2

I see ESPHome 2025.11.0, which claimed wi-fi improvements, was released mid November, so I maybe updated it around the 21st ?

Anyway, yesterday I Cleaned Build Files, done a recompile of my full greenhouse.yaml using ESPHome 2025.11.4 (I try to keep up-to-date anyway, despite so few of the changes appearing to be relevant), and loaded to my greenhouse ESP32 which is still on my work desk.

So far there have been no -128dB Wifi Signal Strength values recorded.

3

And of course - now that I am properly documenting - the Wi-fi signal strength since monday has not gone below -61dB.

I assume that some ESPHome update actually fixed the problem, and maybe I just didn’t catch the window to upload the newer firmware during an awake period, making it feel as though the problem hadn’t been fixed.

4

Nope. Problem occurred again today, but this time I have evidence … so github issue created.

My evaluation is that:

  • ESPHome wi-fi component initialises Wi-fi Signal Strength indicator with value -128.
  • When Wi-fi connects the actual value of Signal Strength is recorded.
  • In some cases - I think if ESPHome tries to report on Wi-fi signal strength before wi-fi is fully initialised - I suspect that it buffers the message with -128dB value, and sends when wi-fi does connect.
  • i suspect it is showing because I have over 700 lines of YAML, and so the initialisation code is overlapping the start of reporting component values.

This issue has played havoc with my history/reporting; but has not otherwise adversely affected my ESPHome operation.