Climate

Under the Köppen climate classification, Guadalajara has a humid subtropical climate (Cwa) that is quite close to a tropical climate, featuring dry, mild winters and warm, wet summers. Guadalajara's climate is influenced by its high altitude and the general seasonality of precipitation patterns in western North America. Although the temperature is warm year-round, Guadalajara has very strong seasonal variation in precipitation. The northward movement of the Inter-Tropical Convergence Zone brings a great deal of rain in the summer months, whereas for the rest of the year, the climate is rather arid. The extra moisture in the wet months moderates the temperatures, resulting in cooler days and nights during this period. The highest temperatures are usually reached in May averaging 33 °C (91 °F), but can reach up to 39 °C (102 °F) just before the onset of the wet season. March tends to be the driest month and July the wettest, with an average of 273 millimetres (10.7 in) of rain, over a quarter of the annual average of about 1,002 millimetres (39.4 in). During the rainy season, afternoon storms are very common and can sometimes bring hail flurries to the city. Winters are relatively warm despite the city's altitude, with January daytime temperatures reaching about 25 °C (77 °F) and nighttime temperatures about 10 °C (50 °F). However, the outskirts of the city (generally those close to the Primavera Forest) experience in average cooler temperatures than the city itself. There, temperatures around −4 °C (25 °F) can be recorded during the coldest nights. Frost may also occur during the coldest nights, but temperatures rarely fall below 0 °C (32 °F) in the city, making it an uncommon phenomenon. Cold fronts in winter can sometimes bring light rain to the city for several days in a row. Snowfall is extremely rare, with the last recorded one occurring on December 1997, which was the first time in 116 years, since it last fell in 1881.

Climate data for Guadalajara, Mexico (1951–2010) Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Record high °C (°F) 35.0 (95) 38.0 (100.4) 39.0 (102.2) 41.0 (105.8) 39.0 (102.2) 38.5 (101.3) 37.0 (98.6) 36.5 (97.7) 36.0 (96.8) 35.0 (95) 32.0 (89.6) 33.0 (91.4) 41.0 (105.8) Average high °C (°F) 24.7 (76.5) 26.5 (79.7) 29.0 (84.2) 31.2 (88.2) 32.5 (90.5) 30.5 (86.9) 27.5 (81.5) 27.3 (81.1) 27.1 (80.8) 27.1 (80.8) 26.4 (79.5) 24.7 (76.5) 27.9 (82.2) Daily mean °C (°F) 17.1 (62.8) 18.4 (65.1) 20.7 (69.3) 22.8 (73) 24.5 (76.1) 23.9 (75) 22.0 (71.6) 21.9 (71.4) 21.8 (71.2) 21.0 (69.8) 19.2 (66.6) 17.5 (63.5) 20.9 (69.6) Average low °C (°F) 9.5 (49.1) 10.3 (50.5) 12.3 (54.1) 14.3 (57.7) 16.4 (61.5) 17.3 (63.1) 16.5 (61.7) 16.4 (61.5) 16.5 (61.7) 14.9 (58.8) 12.1 (53.8) 10.3 (50.5) 13.9 (57) Record low °C (°F) −1.5 (29.3) 0.0 (32) 1.0 (33.8) 0.0 (32) 1.0 (33.8) 10.0 (50) 9.0 (48.2) 11.0 (51.8) 10.0 (50) 8.0 (46.4) 3.0 (37.4) −1.0 (30.2) −1.5 (29.3) Rainfall mm (inches) 15.6 (0.614) 6.6 (0.26) 4.7 (0.185) 6.2 (0.244) 24.9 (0.98) 191.2 (7.528) 272.5 (10.728) 226.1 (8.902) 169.5 (6.673) 61.4 (2.417) 13.7 (0.539) 10.0 (0.394) 1,002.4 (39.465) Avg. rainy days (≥ 0.1 mm) 2.1 1.2 0.7 1.1 3.5 15.2 21.6 20.0 15.5 6.4 1.8 1.8 90.9  % humidity 54 48 45 40 43 61 72 73 73 67 60 60 58 Mean monthly sunshine hours 219.6 239.3 264.9 264.3 291.1 221.5 198.5 210.7 191.1 223.5 232.3 187.0 2,743.8 Source #1: Servicio Meteorológico Nacional Source #2: Colegio de Postgraduados (humidity and sun 1951–1980)