Starting problem: Engine won,t crank, but has juice.

[70GTORAG]

I have a 2000 silverado 5.3l with a nine month old battery. Went to start the truck this morning and it wont even crank. I don't know how else to explain the problem other than when the key is in the accessory position all the normal items work fine, like the radio, the buzzer, and all the typical gauges and lights in the instrument panel work as usual. When I turn the key to the start position, there is no crank-no sound, nothing.
This has happened once before about six months ago-although the truck started later in the day so I have just ignored it as the truck has started without any problems until today.
It seems that it is affected by temperature and humidity. We had rain overnight so the humidity is high. Temperature is about 68 this morning. Could the moisture be affecting the starter relay or some other electrical component? Or am I off base looking in the wrong direction, does it have anything to do with the security system? Anybody have any ideas.

[guumbah]

Do you hear the solenoid click? If not, could be a relay. If so, probably the starter. I had a problem on an old Ford years ago with similar symptoms. Starter motor had a bad spot, and would sometimes not crank at all unless I hit it with a hammer or large wrench. Problem went away completely with new starter.