Temperature Spike? No equipment malfunction

[FrickMasterFlex]

Very interesting situation going on with my tank currently, and let me preface by saying it is not at all an emergency. Temperature jumped from 79 to 82 degrees the other day, and it's stayed there. I know temperature fluctuations are totally fine, and very normal, but I've had no issue keeping a consistent temperature the last 3 months and this was quite random. I try to simulate the ocean as much as possible in my nano by skipping a feeding day here and there, doing a single feeding one day, double feeding another day, etc. Any idea why it may have jumped up and stayed there? All equipment is calibrated and working 100% fine. Only realistic thing I can think of is sunlight from my window in the basement, so I shut the blind today to see if that helps at all. I doubt a spike can be caused by anything alive in the tank, could it?

 

[Jeffcb]

Now that the temp here were I live is rising I have noticed my temp in the tank spiking 80-81.
I tried turning off different equipment for the day to figure out what was causing it and found it is the lights.
My tank is only a few months old and finally running lights at full power. For me its the lights. Going to keep AC at 77.
Doing that it runs at 78 at night and about 79.5 by the end of the day.

 

[FrickMasterFlex]

Ironically enough we did have temps crack the 70's for the first time in months the other day (I'm in NJ). Today it's 22 degrees out so I'm assuming/hoping when I get home later the temperature will have dropped down again. I figured this was the root cause of the issue, just wanted to rule out that it wasn't from anything living inside the tank, as stupid as that may sound. But I'm a new reefer, so there are not stupid questions for me.