The Guam Marathon - March. The Guam Marathon is situated in a semi-tropical climatic zone, average temperatures in the middle 80's and tending toward humid. The Guam Marathon should be considered among the more difficult and not a race to bring a personal record. Race begins at 4:00 a.m. to avoid the heat of mid-morning temps. Start is at the University of Guam Fieldhouse. The entire course is on paved asphalt. The first half of the course is hilly with a gradual and consistent upward incline. Headwinds are known to be pretty stiff on the first half as well, but some years they settle down. The second half of the course flattens out and actually moves gradually and consistently downhill. The final two miles of the course passes through the tourist district of Tumon, and area that has seen much investment and landscaping improvements. The finish empties into Ypao Park and as one goes through the finishing tower they are greeted by the aquamarine blue of Tumon Bay. If one desires they may proceed through and directly into the inviting waters increasing the drama considerably. The course traverses the entire northern half of the island passing through several of the more rural villages (Mangilao, Barrigada, Yigo, Fingayan) and ending in the most developed resort mecca in the region (Tumon).