Mt. Fuji is currently classified as an active volcano with a low risk of eruption.

It appeared in its present form about 10,000 years ago.

About 300,000 people climb Mount Fuji a year.

Climbing season is July and August.

Average temperature at summit is 43 degrees F. in July and August.

Mt Fuji's summit is 12388 feet.
 
It is the 29th tallest volcano in the world.

The crater at the summit has a diameter of about 2624 feet, a depth of 656 feet and a circumference of about 1.24 miles.

The mountain’s diameter at base is about 24.2 miles east-west, 23.6 miles north-south

About 2.2 billion tons of rain and snow fall on the mountain each year; that's 11,000 tankers, each with a capacity of 200,000 tons.

The Japanese archipelago is thought to lie above the edges of five tectonic plates: the Pacific Plate, North American Plate, Philippine Sea Plate, Amur Plate and Nankai Micro Plate. The movement of these plates makes Japan more prone to earthquakes and volcanic eruptions than almost any other country.  Mount Fuji is located just about in the middle of the archipelago, almost directly above where three of the plates meet.

In late 2000, monitoring stations noticed a rapid increase in the number of low-frequency quakes around Mount Fuji, indicating that magma was on the move again underground, and reminding everyone that Fuji is still an active volcano. Japan's national government and the governments of municipalities located around the mountain were concerned, and in 2001 they asked volcanologists to produce a “hazard map” to estimate the damage that could occur during a major eruption. The scientists reported that if volcanic activity on the scale of the Hoei eruption of 1707 were to happen, flows of lava would sever the Tomei Expressway and the Tokaido Shinkansen line. Volcanic ash would rain down on all of Greater Tokyo.

Fuji has been mostly quiet for 300 years. Its life span has been hundreds of thousands of years and three centuries are almost no time at all. It would be perfectly normal for the mountain to become active again. After all, it's only resting.

Links:

http://web-japan.org/nipponia/nipponia35/en/feature/index.html Good article, many pages of photos, facts and stories.

http://www.volcano.si.edu/world/volcano.cfm?vnum=0803-03=

My climb to the summit to see the sunrise.

And some photos.