NFP is not generic. What method do you use? You would want charts that follow the method you are trained to use. It is not a "DIY" kinda thing where you download a chart and go.
Well I forget the name of it but I think we use rule K. It's hard to go by temperature because we have a son that lives on a breathing vent. so we are getting up in the middle of the night a lot and from what I understand to go by temperature you have to have a good nights rest, which we never do. So my wife usually waits for four dry days in a row before we have relations. I just want to start charting again to see where we are.
Sounds as if you are using a method like Creighton or Billings or Marquette or the Famfom method.
This resource will direct you to the website of the method you use, they can assist with the proper charts! http://www.catholicmom.com/nfp_methods.pdf