Elevations above sea level range from 800 feet in the city to 1200 feet on the adjacent uplands. The dominant climatic feature of the New Castle area is the prevailing westerly winds which in turn bring weather systems that originate in continental regions. A southwesterly component of these winds, however, periodically brings in moisture from the Gulf of Mexico resulting in increased humidity and precipitation. Further modification is also produced locally by the industrial activities in the valley which tend to warm the climate, alter th properties of the atmosphere in the lower levels, and affect the hydrologic cycle to some extent. The end product of all these factors is a humid continental climate that features cold winters of serveral months duration broken periodically by brief and occasionally rapid warming, warm and generally humid summers, and a precipitation regime that normally provides adequate amounts of water throughout the year.
Maximum precipitation occurs during the spring and summer seasons.
The weather is subject to variety with noticeable changes in temperature, wind, humidity, cloudiness and other weather elements every few days. On occasion, however, some weather situations may persist for several days to a week or more. Variations in seasonal weather from year to year is a characteristic of the climate. During the cold season which extends from November through most of March, temperatures vary widely from day to day but the range within a 24 hour period is normally smaller than at any other time of the year. Several frigid outbreaks of a few days to a week or more in duration can be expected during the December through February period.