Will not turn over or start

i have replaced the starter before on it not more than a year and half ago. I have had some issues with it not starting immediately over the last week where it would have a delay after switching over the key before the engine would start. Though last night with the cold weather i tried to switch it over and it would not start, it just makes a clicking sound. All the lights on the inside are working, radio, etc. Though once you go to switch over the ignition it just makes like a clicking sound and all the lights flicker in and out before it just decides not to start. I am not sure if its the starter, or ignition, battery, wiring, so what can i do and what do you think is most likely?