Noise margin dropping dramatically in this hot weather

My SNR margin seems to drop dramatically when its warm. Today, hottest day here so far this year, SNR margin dropped from 7.5dB at 07:00hrs to 2.5dB at 15:00hrs. Router (Speedtouch) stayed in sync but notched up 1.5million FECs.

BTW this is 7km of overhead wire all the way to the exchange and seems to be a pattern in this warm(er) weather.

Is this typical or does it indicate a poor connection somewhere?

Regards

Not typical, maybe someone has an electrically noise aircon unit switched on, or overhead cable expanding and now in contact with trees that are affecting signal

We had a shedload of problems with trees last year. You could be on to something there.

Latest stats

Uptime: 8 days, 4:20:09
Modulation: G.992.1 Annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 2,080
Data Transferred (Sent/Received) [MB/MB]: 168.21 / 941.14
Output Power (Up/Down) [dBm]: 11.5 / 17.0
Line Attenuation (Up/Down) [dB]: 31.5 / 63.5
SN Margin (Up/Down) [dB]: 6.0 / 4.0
Vendor ID (Local/Remote): TMMB / 
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 94,694 / 0
FEC Errors (Up/Down): 2,658 / 3,690,794
CRC Errors (Up/Down): 404 / 113,400
HEC Errors (Up/Down): 200 / 84,348

Rgds