Getting my ESP8266 working

Alright, the ESP is an MCU by itself, far more powerful than the UNO, but here its only used as a module to give WIFI connectivity through the serial port to the UNO. You have AT commands that you will need to use to perform all kind of network operations, you will need to connect to the WIFI, then connect to Thingspeak and send data. The way you do that is through the UNO, uno will send AT commands to the module to perform all those operations.

So if I read that right. What your saying is I need to tell the uno to send AT commands to the ESP8266 and that's how they will talk and send data?

So what I'm wanting to do with it is:

Measure light levels to determine sunrise and sunset

Mark the time of both sunrise and sunset

Calculate the amount of sunlight

Turn on a light at a calculated time (based on sunlight duration) so that the next day should have at least 16 hours of light.

On top of that I want to measure temp/humidity both inside and outside.

I would like the light levels and temp/humidity sent to thingspeak so I can keep track

Project is for a chicken coop.

I would suggest you to use astronomy based algorithms to compute the sunrise and sunset, as they are not affected by clouds, mist or what not (there are probably websites that can give you the exact sunrise and sunset for each time/day). Do you have all the sensors that do what you want to do? I did something similar, but with different sensors in my roadtest (Sensirion Environmental Sensor Shield - Review ). I measured temperature, relative humidity, VOC levels and CO2eq levels and sent data to the Thingspeak server during 20 days. I used an ESP32, which is similar to the ESP8266. To send data I just performed an HTTP GET operations for each entry, which was recorded once every 30 s.

Even the ESP8266-001 module has 4 pins available and it can be used standalone to do some interesting stuff involving I2C and one-wire sensors.

It has enough memory to store a wifi functions library, so it should be possible to use that instead of using low level AT commands.

I have everything for it sensors I planned to use:

Photoresistor

RTC module

DHT 11

using the Photoresistor mainly because I know how. Not sure how to pull the times off the internet. That would be better. However doesn't have to be horrible accurate. Plus should I loose WiFi (it is kind far from the house and connectivity can be spotty) the time can still be calculated

I'm starting to think that may be the best way to go. Can I use the same Arduino code?

You are right, but considering that the 8266 costs 3 usd, why bother...

Pulling time from the internet with the ESP32 is pretty straightforward, just a few lines of code and that's it. Unless you turn the ESP off you don't need more than one time sync. If electricity gets interrupted frequently, you could use a battery.

Plan is to have it solar with battery

Then its all good, sync time just once and forget about it. Capture data from sensors and keep it in a buffer, as soon as you get connectivity you upload it to Thingspeak, and thats it

You make it sound so simple

You make it sound so simple