|Information courtesy of the National Climate Data Center|
|Barrow is the most northerly First-Order station operated by the National Weather Service. Although this station generally records one of the lowest mean temperatures for the winter months, the surrounding topography prevents the establishment of the lowest minima for the state. With the Arctic Ocean to the north, east, and west, and level tundra stretching 200 miles to the south, there are no natural wind barriers to assist in stilling the wind, permitting the lowering of temperatures by radiation, and no downslope drainage area to aid the flow of cold air to lower levels. Consequently, temperature inversions in the lower levels of the atmosphere are not as marked as those observed at stations in the central interior.
Temperatures at this northern station remain below the freezing point through most of the year, with the daily maxima reaching higher than 32 degrees on an average of only 109 days a year. Freezing temperatures have been observed every month of the year. February is generally the coldest month and March temperatures are but little higher than those observed in the winter months. In April, temperatures begin a general upward trend, with May becoming the definite transitional period from winter to the summer season. July is the warmest month of the year and the frequency of minimum temperatures of 32 degrees or less are about one day out of two for July and August. During late July or early August, the Arctic Ocean is usually ice-free for the first time in summer. The end of the short summer is reached in September. By November about half of the daily mean temperatures are zero or below, and Barrow definitely returns to the clutches of winter cold. At 1250 p.m. on November 18, the sun dips below the horizon and is not seen again until 1151 a.m. on January 24. Then the amount of possible sunshine each day increases by never less than 9 minutes per day. By 106 a.m. on May 10th the possible sunshine has increased to 24 hours per day. The sun remains visible from that time to August 2, when it again sets for 1 hour and 25 minutes. The decrease in hours of sunshine is as rapid as the increase.
The amount of sunshine appears to have a direct relationship to the occurrence of cloudiness, precipitation, and heavy fog. All three build up to a maximum along with the hours of sunshine. Maximum cloudiness does continue into the fall months, although the amount of sunshine, precipitation, and fog are on the decrease. Since an accurate estimate of cloudiness cannot be made under conditions of darkness, the record of cloudiness for that time is not summarized. However, average cloudiness probably approximates that observed during late winter and spring months.
Variation of wind speed during the year is small, with the fall months being windiest. Extreme winds in the upper 40s and low 50s have been recorded for all months.