Weather — Oaxaca
Despite lying deep in southern México, most of Oaxaca enjoys moderate temperatures year round, except for the coast and the Isthmus, which bask in endless tropical summer, and the sierras, where in the winter at higher elevations temperatures can sometimes dip below freezing at night.
Rainfall, however, does change seasonally. Like most of México, Oaxaca has a distinct wet and dry season, each lasting about six months. The dry season normally begins in mid-fall and runs through the end of May. The skies are usually clear and it rarely ever rains. The rainy season normally begins in late May or early June and tapers off by late October, sometimes lasting into early November. During the rainy season, rain doesn't fall continuously for months on end. Rather, mornings usually begin sunny, staying clear until the afternoons, when clouds build up and showers break out almost daily, capping off the worst of the days' heat. When the showers do come after a six month absence, the soil moistens, the landscape after having laid dormant becomes lush and green again, staying so until December. In the fall, showers abating, the soil starts to dry, the landscape slowly becoming browner and dustier until the following June, when the rains begin again.
The city of Oaxaca and its surrounding valleys have a reputation for spring-like weather year round. Late fall and Winter are the coolest and most pleasant seasons. Daytime highs typically reach the mid-70s to around 80°F (23-27°C), while overnight lows cool to the mid-40s to mid-50s °F (6-12 °C). Spring, before the rains begin, is usually the warmest. Spring-time highs typically reach the mid-80s to around 90°F (29-32°C) and overnight lows cool to a pleasant mid-50s to low 60s °F (12-17°C). With the arrival of afternoon summer showers, daytime highs cool slightly from springs' highs. Summer and early fall temperatures typically peak in the high 70s to low 80s (25-28°C) and overnight lows cool to the high 50s to low 60s (14-17C). In the surrounding sierras, expect similar year-round weather, only the rains are more frequent and intense and the temperatures are cooler, even sometimes dropping below freezing for overnight lows at higher elevations.
Jan Feb March April May June July Aug Sept Oct Nov Dec High 78°F 82°F 85°F 87°F 84°F 80°F 79°F 79°F 78°F 78°F 78°F 78°F 26°C 28°C 29°C 31°C 29°C 27°C 26°C 26°C 26°C 26°C 26°C 26°C Low 47°F 49°F 53°F 57°F 59°F 60°F 59°F 59°F 59°F 56°F 50°F 47°F 8°C 9°C 12°C 14°C 15°C 16°C 15°C 15°C 15°C 13°C 10°C 8°C
Of all of Oaxaca, the Pacific coast and the Isthmus feel the most tropical. Throughout the year, there is little change in daily high and low temperatures, especially the Isthmus. During the dry season, high temperatures typically peak in the high 80s to low 90s (31-34°C), while overnight lows drop to the mid-60s to low 70s (18-23°C). During the rainy season, mornings usually begin clear and humid with overnight lows in the mid-60s (17-19°C). In the afternoons, high temperatures typically peak in the high 80s to mid-90s (31-36°C), almost always ending in afternoon showers or thunderstorms.
Jan Feb March April May June July Aug Sept Oct Nov Dec High 92°F 94°F 94°F 95°F 94°F 91°F 91°F 91°F 90°F 92°F 91°F 93°F 33°C 34°C 34°C 35°C 34°C 33°C 33°C 33°C 32°C 33°C 33°C 34°C Low 65°F 65°F 67°F 69°F 71°F 71°F 70°F 71°F 70°F 69°F 67°F 66°F 18°C 18°C 19°C 21°C 22°C 22°C 21°C 22°C 21°C 21°C 19°C 19°C