Luxembourg, a small country between Belgium, France and Germany, has a moderately continental climate, with cold winters and mild summers. The influence of the Atlantic Ocean is evident, but the altitude, which varies between 250 metres (800 feet) in the far south and 500 metres (1,650 feet) in the north, makes it a bit colder than the plains, with more frequent snowfalls in winter.
Here are the average temperatures in the capital city, which is located in the south, at about 300 metres (1,000 feet) above sea level.
Luxembourg - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)-2-124811131310620
Max (°C)3591318212323181374
Min (°F)283036394652555550433632
Max (°F)374148556470737364554539

Winter, from December to February, is cold and dull. In the capital, the average temperature in January and February is around freezing (0 °C or 32 °F), or slightly higher. When Atlantic currents become more intense, there can be mild days, though cloudy and windy. On the contrary, when currents from eastern Europe prevail, the temperature can dip well below freezing.
Spring, from March to May, initially cold, becomes gradually cool and then mild, so much so that in April the maximum temperatures are around 13 °C (56 °F), and in May around 18 °C (64 °F). However, the weather is unstable, and while until mid-May it can still be cold, starting from mid-May, on sunny days thunderstorms can erupt in the afternoon.
Summer, from June to August, is mild or pleasantly warm, with cool nights and pleasant days: the minimum temperature hovers around 13 °C (56 °F), while the maximum temperature is around 23 °C (73 °F). There is no shortage of cool and rainy days, when the country is affected by Atlantic fronts, but they alternate with sunny and warmer days, with peaks of 30/32 °C (86/90 °F), though these hot days are fairly rare.
In Autumn, from September to November, the weather is often gray, wet and rainy, especially in the second part, and at times windy.

Luxembourg

Precipitation in Luxembourg is quite frequent, and relatively abundant, amounting to around 700 millimetres (27.5 inches) per year in the south-east, and around 900 mm (35 in) in the south-west, while in the northern area, located at higher altitudes, it reaches 1,000 mm (40 in).
Here is the average precipitation.
Luxembourg - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)756070607780707575857585890
Prec.(in)32.42.82.433.12.8333.333.335
Days12101210111110109111213129

The amount of sunshine, low from November to February, is not great in the other seasons, but it's acceptable between April and August, when there are 6/7 hours of sunshine per day on average.
Luxembourg - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours225677765311

When to go



The best time to visit Luxembourg runs from mid-May to mid-September, when the temperature is generally pleasant and the weather is variable, so that the sun alternates with cloudy skies, and also rains and thunderstorms. The second half of September begins to be more cool and cloudy, but in this period the forests show the bright colours of autumn.

What to pack



In winter: warm clothing, sweater, down jacket, raincoat or umbrella.
In summer: clothes for spring and autumn, t-shirts, but also long pants, jacket, sweatshirt or sweater for the evening and for cooler days; raincoat or umbrella.