Zürich has, depending on the definition used, an oceanic climate , but in the higher areas it is defined as a humid continental climate (Dfb, using 0 °C isoterm) with warm summers and four distinct seasons. Decisive for the climate of Zürich are both the winds from westerly directions, which often result in precipitation and, on the other hand, the Bise (east or north-east wind), which is usually associated with high-pressure situations, but cooler weather phases with temperatures lower than the average. The Foehn wind, which plays an important role in the northern alpine valleys also has some impact on Zürich.
The annual mean temperature at the measuring station of the Federal Office of Meteorology and Climatology in Zürich-Fluntern (556 m[1,824 ft] above sea level on the slope of the Zürichberg, 150 m[490 ft] above the level of the city centre) is 9.3 °C (48.7 °F). The lowest monthly mean of daily minimum temperature are measured in January with −2.0 °C (28.4 °F) and the highest monthly mean of daily maximum temperature are measured in July with 24.0 °C (75.2 °F). On average there are 74.9 days in which the minimum temperature is below 0 °C (32 °F) (so-called frost days), and 23.7 days in which the maximum temperature is below 0 °C (32 °F) (so-called ice days). There are on average 30 so-called summer days (maximum temperature equal to or above 25 °C [77 °F]) throughout the year, while so-called heat days (with maximum temperature equal to or above 30 °C [86 °F]) are 5.8 days.
The average high temperature in July is 24.0 °C (75.2 °F) and average low temperature is 14 °C (57.2 °F). The highest recorded temperature in Zürich was 37.7 °C (100 °F), recorded in July 1947, and typically the warmest day reaches an average of 32.2 °C (90.0 °F).
Spring and autumn are generally cool to mild, but sometimes with large differences between warm and cold days even during the same year. The highest temperature of the month March in 2014 was on the 20th at 20.6 °C (69.1 °F) during a sunny afternoon and the lowest temperature was on the 25th at −0.4 °C (31.3 °F) during the night/early morning. Record low of average daily temperatures in March since 1864 is −12 °C (10 °F) and record high of average daily temperatures in March is 16 °C (61 °F). Record low of average daily temperatures in October is −16 °C (3 °F) and record high of average daily temperatures in October is 20 °C (68 °F).
Zürich has an average of 1,544 hours of sunshine per year and shines on 38% of its potential time throughout the year. During the months April until September the sun shines between 150 and 215 hours per month. The 1,134 millimetres (44.6 in) rainfall spread on 133.9 days with precipitation throughout the year. Roughly about every third day you will encounter at least some precipitation, which is very much a Swiss average. During the warmer half of the year and especially during the three summer months, the strength of rainfall is higher than those measured in winter, but the days with precipitation stays about the same throughout the year (in average 9.9–12.7 days per month). October has the lowest number (9.9) of days with some precipitation. There is an average of 59.5 so-called bright days (number of days with sunshine duration greater than 80%) through the year, the most in July and August (7.4, 7.7 days), and the least in January and December (2.7, 1.8 days). The average number of days with sunshine duration less than 20%, so-called cloudy days, is 158.4 days, while the most cloudy days are in November (17.8 days), December (21.7 days), and January with 19 days.