Vasteras, where it's located

The climate of Västerås is Baltic, that is, moderately continental, with cold winters, during which the average temperature is a few degrees below freezing, and mild to pleasantly warm summers.
The city is located in southern Sweden, about 70 km (45 mi) west of Stockholm, on the shores of Lake Mälaren.
The average temperature of the coldest month (January) is of -2.8 °C (27 °F), that of the warmest month (July) is of 18.4 °C (65 °F). However, during polar cold spells, the temperature can drop to -25 °C (-13 °F) or below, while in summer, it can reach 28/30 °C (82/86 °F), although rarely. Here are the average temperatures.
Vasteras - Average temperatures
Min (°C)-5-5-316101413941-3
Max (°C)0041217202321171052
Min (°F)232327344350575548393427
Max (°F)323239546368737063504136

Precipitation amounts to 610 millimeters (24 inches) per year: so, it is at an intermediate level. It ranges from 25 mm (1 in) in the driest month (March) to 80 mm (3.1 in) in the wettest (August). Here is the average precipitation.
Vasteras - Average precipitation


Best Time

The best time to visit Västerås is the summer, from June to August, since it is the mildest season. However, you must take into account some rainy days and a bit of cold at night.