The Peruvian coast line runs nearly parallel to the eclipse track as it approaches from the northwest and the center line runs along the beaches between San Juan and Mollendo. South of Mollendo it leaves the waterfront, turning eastward to climb the steep slopes of the western branch of the Andes, the Cordillera Occidental. The offshore trade winds blow monotonously out of the south, but against the land they are turned by the mountains to flow parallel to the coast. Some of the most persistent sea breezes in the world draw the winds inland and carry cloud against the slopes of the Andes. Day after day a dismal low stratus cloud covers the coast, bringing dense chilly fog and persistent drizzle to the slopes. By November the unyielding cloudiness of winter begins to feel the effects of the upcoming summer and the overcast becomes less tenacious. Occasional sunny days replace the gloom, but the area remains heavily clouded with only a quarter to a third of the mornings showing clear skies. Because the southerly trade winds strike the coast most directly at Tacna, the cloud piles up here more than in any other area.
The secret to finding good eclipse weather along the Peruvian coast is to go inland and uphill. As noted above, the marine cloud is not very deep - usually less than 900 meters, especially in November. Sites can easily be found which remain above the cloud since the land rises very steeply. Satellite pictures show that the cloud hugs the contours of the land, flowing into every coastal valley, and bypassing every ridge and rise of land. One ridge of higher ground that provides a vantage point from which to see the eclipse lies inland and south of Mollendo. Day after day the satellite images showed this ridge protruding above the clouds in the early morning. This ridge and the plateau beyond it is accessible from the Pan American Highway that leads from Arequipa to Mollendo.
If traveling toward Mollendo from Arequipa, don't proceed beyond Guerreros Estación unless the lower slopes are cloud-free. Guerreros Estación is a small railway stop, about 15 kilometers north of the center line, lying at 1140 meters above sea level. This should be high enough to escape all but the deepest marine cloudiness, but it will come with a small time penalty because of its distance from the center of the track. If you insist on trying for the center line at Mollendo, the best strategy is to find the edge of the marine cloud on the Arequipa highway and set up in the dry air just above. You can find this point coming from either direction. Those who are most daring will select a spot at the cloud edge, trusting that the gray mist will not move farther inland as the morning sun warms the slopes. More cautious observers will give up a few seconds of totality to move farther uphill - a few hundred meters at least. Even if Mollendo is clear on eclipse morning, there is a danger that clouds will reform and move inland as temperatures drop ahead of totality. If the air is very humid or clouds have recently cleared, the danger is even greater and a higher altitude is prudent. One clue to watch is the character of the vegetation. Plants near the ocean get their moisture from the fog-drip of the marine clouds. Where clouds are rare, the vegetation will be sparse or of a desert species. Ask around locally.
A more promising location near Arequipa lies at the point where the Pan American Highway crosses the center line on the slopes between Ilo and Moquegua. It is a longer distance to travel but the combination of center line access and good weather prospects make it an attractive alternative. The satellite images from 1991 and 1992 showed that this spot was cloud free about 60% of the time (longitude 71). It is also readily accessible from Tacna. Tacna itself is a cloudy spot, so the trip up the slopes to drier skies may require plenty of lead time. Since the marine cloud may be pushed right up against the mountain side, conditions could be foggy and damp along the road. Tacna has one of the highest frequencies of fog in Table 14. If you travel at night to catch this sunrise eclipse at the center line, be especially generous with your time as visibility may then be at its poorest due to overnight and morning fog. Roads northeast from Tacna lead directly to the center line near Tarata, rather than northwestward to Moquegua. In Figure 9, this spot has a 15% greater frequency of sunny weather (longitude 70 deg W) than at Moquegua. If the route is passable, this may be the best location from Tacna, especially as it is a much shorter journey.
The statistics at Arequipa, which Table 14 shows to be a very sunny location, are typical for the skies on the slopes above the marine cloud deck. At an altitude of nearly 8500 feet, Peru's second city is well above the coastal cloud. The climatological record shows that sunny skies are measured on two days out of three at eclipse time.
Chile also offers an opportunity to reach the middle of the eclipse path as the shadow track does cut the extreme northeast corner of the country. The road leads northward and upward from Arica, and is apparently very rough. Travel will likely be slow and bumpy, but the route does eventually lead onto the Altiplano and into La Paz. The rail line from coastal Arica to the altiplano also merits some investigation. The center line above Arica enjoys a high frequency of sunshine - perhaps over 80%.
