This report describes the historical weather record at the Ralph M. Calhoun Memorial Airport (Tanana, Alaska, United States) during 1971. This station has records back to July 1948.
Tanana, Alaska has a humid subarctic continental climate with cool summers and no dry season. The area within 25 mi of this station is covered by forests (94%) and lakes and rivers (4%)
Daylight saving time (DST) was observed at Tanana, Alaska during 1971. There were two time changes during 1971:
1971 was not a leap year, so it has 365 days and no February 29th. The first leap year before 1971 was 1968 and the first after was 1972.
The summer and winter solstices and the spring and fall equinoxes mark the passing of the seasons. They fall on nearly the same day each year, with differences of a day or two depending on the year. In 1971 they occurred on:
|Spring Equinox||Sunday, 21 March 1971.|
|Summer Solstice||Tuesday, 22 June 1971.|
|Fall Equinox||Thursday, 23 September 1971.|
|Winter Solstice||Wednesday, 22 December 1971.|
The hottest day of 1971 was February 21, with a high temperature of 22°F. For reference, on that day the average high temperature is 8°F and the high temperature exceeds 25°F only one day in ten. The hottest month of 1971 was February with an average daily high temperature of -5°F.
Relative to the average, the hottest day was January 4. The high temperature that day was 13°F, compared to the average of -3°F, a difference of 16°F. In relative terms the warmest month was February, with an average high temperature of -5°F, compared to an typical value of 5°F.
The month of February had the largest fraction of warmer than average days with 21% days with higher than average high temperatures.
The coldest day of 1971 was January 24, with a low temperature of -61°F. For reference, on that day the average low temperature is -14°F and the low temperature drops below -44°F only one day in ten. The coldest month of 1971 was March with an average daily low temperature of -36°F.
Relative to the average, the coldest day was February 24. The low temperature that day was -61°F, compared to the average of -9°F, a difference of 52°F. In relative terms the coldest month was March, with an average low temperature of -36°F, compared to an typical value of -2°F.
The longest cold spell was from January 12 to February 6, constituting 26 consecutive days with cooler than average low temperatures. The month of January had the largest fraction of cooler than average days with 84% days with lower than average low temperatures.
The longest freezing spell was from January 1 to March 11, constituting 70 consecutive days with temperatures strictly below freezing.
The clearest month of 1971 was January, with 39% of days being more clear than cloudy. The longest spell of clear weather was from January 15 to January 19, constituting 5 consecutive days that were clearer than they were cloudy.
The cloudiest month of 1971 was February, with 50% of days being more cloudy than clear. The longest spell of cloudy weather was from February 5 to February 11, constituting 7 consecutive days that were cloudier than they were clear.
This station provides hourly reports of significant weather events at and around the station, but does not report the quantity of precipitation at the station itself. This is common for weather stations located outside of the United States, and for a small subset of stations in the United States that are located at lesser used and smaller airports.
This station reports when significant weather events (including precipitation) are visually observed at or near the station. Such events do not always correspond to measured quantities of liquid equivalent precipitation, such as when the event is near by not at the station, or in the case of solid precipitation that does not melt in the collection basin.
The day in 1971 with the most precipitation observations was January 5. There were 5 hourly weather reports that day (out of a maximum of 24) in which some form of precipitation was observated at or near the station. The month with the most precipitation observations was February, with 37 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from March 11 to December 31, constituting 296 consecutive days with no observed precipitation. The months April, May, June, July, August, September, October, November, and December were completely without observed precipitation.
The month with the largest fraction of days with at least some observed precipitation was February, with 46% of days reporting some observed precipitation.
In this section we consider only those weather reports that indicate liquid precipitation. For the purposes of this analysis, we include thunderstorms even though some thunderstorms are not accompanied by liquid precipitation.
The month of 1971 with the largest number of those reports was January, with a total of 0 reports. The day with the largest number of those reports was January 1, with a total of 0 reports.
This station reports when snow is observed falling but does not report the quantity of snow that has fallen or the depth of snow on the ground.
In this section we consider hourly weather reports that contain an observation of falling snow. These reports do not necessarily correspond to accumulation.
The first reported snow fall in 1971 was on January 1; the last was on March 10. The month of 1971 with the largest number of those reports was February, with a total of 37 reports. The day with the largest number of those reports was January 5, with a total of 5 reports.
Humidity is an important factor in determining how weather conditions feel to a person experiencing them. Hot and humid days feel even hotter than hot and dry days because the high level of water content in humid air discourages the evaporation of sweat from a person's skin.
When reading the graph below, keep in mind that the hottest part of the day tends to be the least humid, so the daily low (brown) traces are more relevant for understanding daytime comfort than the daily high (blue) traces, which typically occur during the night. Applying that observation, the least humid month of 1971 was March with an average daily low humidity of 50%, and the most humid month was January with an average daily low humidity of 69%.
But it is important to keep in mind that humidity does not tell the whole picture and the dew point is often a better measure of how comfortable a person will find a given set of weather conditions. Please see the next section for continued discussion of this point.
Dew point is the temperature below which water vapor will condense into liquid water. It is therefore also related to the rate of evaporation of liquid water. Since the evaporation of sweat is an important cooling mechanism for the human body, the dew point is an important measurement for understanding how dry, comfortable, or humid a given set of weather conditions will feel.
Generally speaking, dew points below 50°F will feel a bit dry to some people, but comfortable to people accustomed to dry conditions; dew points from 50°F to 68°F are fairly comfortable to most people, and dew points above 68°F are increasingly uncomfortable, becoming oppressive around 77°F.
To take some examples, and basing our categorization on the daily high dew point in 1971, January had 28 dry days, no comfortable days, and no humid days; April had no dry days, no comfortable days, and no humid days; July had no dry days, no comfortable days, and no humid days; and October had no dry days, no comfortable days, and no humid days.
The highest sustained wind speed was 25 mph, occurring on February 10; the highest daily mean wind speed was 17 mph (February 9);
The windiest month was February, with an average wind speed of 8 mph. The least windy month was March, with an average wind speed of 5 mph.
This station did not reliably report the visibility during 1971.
This station did not reliably report the cloud ceiling during 1971.