Road Cycling - Climbing Categories

I am new to road cycling and I just complted my first century ride around Lake Tahoe. I'v been hearing a lot about Category 1 (2, 3, etc.) climbs and I was wondering what the criteria for the categories are. Coming up empty handed searching the web. Can anyone help?

I can't provide specific details of how the category is calculated, but it is primarily a factor of the length and grade of a climb though other factors are taken into consideratoin. Category 3 is the easiest, 2 harder, etc. The most difficult climbs are designated HC, hors categorie, or "above classification". These are mountains like the Galibier, Alpe d' Huez, etc. climbs in the TDF. If you look at a TDF guide they usually have a graphic depiction of the route, including the category of the rated climbs. Hope this helps some.
Regards,
Raymond

Is there a standard set?

Like elevation gain in feet per mile?

What is 1600 feet over 7 miles considered.

From http://www.lancearmstrong.com/hill.html

General guidelines:
Category 4 - the lowest category, climbs of 300-1000 feet(100-300m).
Category 3 - climbs of 1000-2000 feet(300-600m).
Category 2 - climbs of 2000-3500 ft.(600-1100m)
Category 1 - climbs of 3500-5000ft(1100-1500m)
Hors Category - the hardest, climbs of 5000ft+(1500m+)

*** Steepness also plays a factor in the rating. Most of the big climbs in the Alps average 7-8% where the big climbs in the Pyrenees average 8-9%.

Originally posted by Ba-Dg-Er
From http://www.lancearmstrong.com/hill.html

General guidelines:
Category 4 - the lowest category, climbs of 300-1000 feet(100-300m).
Category 3 - climbs of 1000-2000 feet(300-600m).
Category 2 - climbs of 2000-3500 ft.(600-1100m)
Category 1 - climbs of 3500-5000ft(1100-1500m)
Hors Category - the hardest, climbs of 5000ft+(1500m+)

*** Steepness also plays a factor in the rating. Most of the big climbs in the Alps average 7-8% where the big climbs in the Pyrenees average 8-9%.

Thanks, you rock!

Thanks!!!!!!!!!!!

The other factor taken into account is where in the race the climb occurs. If it is early in the race the climb may be downgraded and alternatively if it is near the end of race it may be upgraded.