What environmental conditions led Viking raids on other countries?

The climate also affected the Scandinavian's seafaring and raiding. Summer storms stopped the movement of the Vikings to new lands and winter sea-ice is one of the causes of the first overwintering for raiding of the Norse on mainland Europe.

where's the

hygrometers and hair thermometers (often found as part of hygrometers/psychrometers) can be used to measure humidity. barometers are used to measure atmospheric pressure, while anemometers are used to measure wind speed. so the 2nd and 4th choices should be the correct answers.