Do the "shake method" mentioned in the video above to make sure the honey is cured. You can also use a refractometer to ensure the moisture content is under 19%.
What are the flowers telling you? Are the major nectar producing flowers in your area still blooming? By July 4th, the vast majority of nectar producing flowers have died in Texas.
Cured honey is typically capped. Frames will often have some cells uncapped, but 80+% are often capped when the honey is ready to harvest.
Are bees starting to uncap and eat the honey? If so, it is time to harvest quickly before the bees eat all the stored honey. Feeding will need to be done after the harvest to ensure the hive has adequate food stores.
Have bees stopped actively drawing out new comb? If so, that is another sign the honey flow has ended.
Are your bees becoming more "robby" and interested in frames of honey when you are inspecting hives? If so, that means there is not as much forage available for them.
Tallow Tassel
Pincushion/Scabiosa
Indian Blanket