The climate of Sion
Sion, a Swiss city nestled in the heart of the Rhone valley, falls under the ET classification in the Köppen climate structure, indicating a tundra climate. This type of weather is characterized by often harsh winters, brief and mildly warm summers, and significant variations in humidity, rain, snow, daylight, and sunshine throughout the year.
Sion's weather ranges from the bitterly cold winters where the lowest temperature can be as chilling as -11°C (12.2°F) in
January and
February, to only moderately warm summers with the highest temperature recorded around 16.7°C (62.1°F) in
August. Humidity remains relatively high throughout the year, peaking at around 90% in
March and dropping to 79% in
July and August.
In terms of precipitation, Sion experiences both rainfall and snowfall. The city gets its maximum rainfall of about 177mm (6.97") in
May whereas the least, around 76mm (2.99"), is in
September. The frequency of rainfall is also the highest in May with about 25.8 days. Snowfall is more common from
November to
April, with a peak in January and February, accumulating as much as 159mm (6.26"). Regarding sunshine, Sion enjoys up to 9.8 hours of sunlight in July and August.
The best time to visit Sion
Considering the temperature and sunshine hours, the best time for tourists to visit
Sion would be from late spring to early autumn. Specifically, these months include
May to
October when the temperature ranges from a pleasant 8.7°C (47.7°F) to a comfortable 16.7°C (62.1°F). Moreover, these months also experience the highest daylight hours, extending from 13.6 hours in
April to 15.7 hours in
June, which allows ample time for outdoor activities.
July and
August, along with the highest temperatures, bring the most sunshine, averaging about 9.8 hours daily, and consequently provide the best climate for a visit.
The worst time to visit Sion
The period between
November to
April would be less ideal for visitation as it marks the cold season in
Sion. During this period, the temperature typically drops from 2.5°C (36.5°F) in November and reaches its lowest, -11°C (12.2°F), in
January. Furthermore, daylight hours reduce significantly, registering a minimum of 8.7 hours in
December. These months are also prone to heavy snowfall, making it highly unfavorable for outdoor-oriented travel, unless winter sports and snow expeditions are the primary goal.
Spring weather in Sion
From
March to
May,
Sion enters its spring season. The temperatures start to rise from the winter lows, averaging between -7.7°C (18.1°F) to 8.7°C (47.7°F). While March and
April still witness occasional snowfall, by May, it almost completely fades away. However, with the melting snow, there is an increase in rainfall volume and frequency, reaching a peak in May. Despite these showers, the amount of sunshine begins to improve significantly during this transitional period, offering more pleasant conditions towards the end of spring.
Summer weather in Sion
Summer in
Sion brings a respite from the harsh winters with the mercury level rising to an average high of 16.7°C (62.1°F). The heat, however, is moderate and far from sweltering.
June to
August witnesses a slight drop in humidity, down to 79%, which contributes to the overall comfort. There is a marginal dip in rainfall, but it is the abundance of sunshine, up to approximately 10 hours in the warmest months, that truly highlights the summer season in Sion.
Autumn weather in Sion
The autumn months, namely
September,
October, and
November, witness a gradual cooling in temperature from the summer warmth. With temperatures ranging from 12.3°C (54.1°F) to 2.5°C (36.5°F), the weather slowly transitions towards the impending winter chill. Rainfall continues to drop during these months, reaching its yearly low in September. However, sunshine hours also start decreasing, indicating shorter days.
Winter weather in Sion
Winter grips
Sion firmly between
December and
February, as temperatures plummet, falling up to -11°C (12.2°F). Snowfall increases dramatically during these months, particularly in December and
January, when it reaches its highest volume. This, combined with the reduced daylight and lower visibility, generally covers Sion in a frosty haze for the significant part of winter. However, this season offers its unique charm and wonder, especially for those intrigued by winter landscapes or interested in winter sports.
Weather in January
Beginning the year, the weather in
Sion,
Switzerland is typically cold, with
January seeing temperatures from -11°C (12.2°F) to -2.5°C (27.5°F) on average. The city experiences numerous days with snow, aligning with the overall Swiss winter atmosphere.
Weather in January »Weather in February
In consistent pattern with
January,
February's weather in
Sion features the similar average temperatures from -11°C (12.2°F) to -2.3°C (27.9°F). The month, however, holds marginally more daylight hours, marking subtle inroads towards Swiss spring.
Weather in February »Weather in March
Transitioning into the warmer months,
March sees a slight rise in average temperatures which now range from -7.7°C (18.1°F) to 0.9°C (33.6°F). The month is characterized by increased daylight hours and a decrease in snowfall compared to
February.
Weather in March »
Weather in April
April truly heralds the arrival of spring in
Sion, with the temperature increase being quite noticeable, ranging from -3.2°C (26.2°F) to 5°C (41°F). This month registers a significant reduction in snowfall, with precipitation occurring mainly as rain, the rainfall peaking at 91mm (3.58") over 22.6 days.
Weather in April » Weather in May
May's weather brings warmer days to
Sion, Zurich, with temperatures continuing their northward move. Sunshine hours also see a considerable surge compared to
April, marking plenteous outdoor opportunities. While rainfall is abound, the frequency of rainy days is significantly less than the previous month, painting a generally favorable weather canvas.
Weather in May » Weather in June
In
June, summer starts to settle in with the average temperatures now ranging between 4.3°C (39.7°F) to 13.9°C (57°F). The weather conditions are generally pleasant, encouraging outdoor activities and exploration of the picturesque Swiss landscapes.
Weather in June »
Weather in July
As one of the two warmest months in
Sion,
July experiences average temperatures between 6.3°C (43.3°F) and 16.5°C (61.7°F). With the city now well into summer, the month registers the highest UV index figure for the year, meaning sunscreen becomes a must-have item.
Weather in July »Weather in August
August's weather in
Sion,
Switzerland echos that of the previous month, with the average temperatures dancing between 6.4°C (43.5°F) and 16.7°C (62.1°F). The month symbolizes the peak summer period, scoring equal to
July in UV index evaluations.
Weather in August » Weather in September
Come
September,
Sion starts to transition from summer towards the autumn season, experiencing temperatures that range from 3.3°C (37.9°F) to 12.3°C (54.1°F). Despite the shortening daylight hours, the city continues to enjoy many sunny days.
Weather in September »
Weather in October
October's weather in
Sion,
Switzerland bears the true mark of autumn. Despite cooler temperatures, the city often enjoys bright, clear days amid colourful vistas of turning leaves. This is the period where the wind speed starts to pick up slightly, adding to the cool feel of the weather.
Weather in October » Weather in November
During
November, the weather in
Sion becomes visibly chillier, lending more credence to the arrival of the Swiss winter. The city witnesses a drop in temperatures compared to
October as well as an increase in precipitation, a mix of rain and snow towards the end month.
Weather in November »Weather in December
In
December,
Sion,
Switzerland braces itself for full-blown winter, with temperatures plummeting to between -9.5°C (14.9°F) and -1.2°C (29.8°F). This month records the highest snowfall at 156mm (6.14") over 7.2 days, turning the city into a winter wonderland.
Weather in December »