This report describes the historical weather record at the Tribhuvan International Airport (Kathmandu, Nepal) during 2012. This station has records back to May 1973.
Kathmandu has a warm temperate climate with dry winters and hot summers. The area within 25 mi of this station is covered by grasslands (69%), croplands (19%), forests (7%), and shrublands (6%)
Daylight saving time (DST) was not observed at Kathmandu during 2012.
2012 was a leap year and thus has 366 days rather than the normal 365. Leap years occur every fourth year and the extra day is always February 29th. In 2012 February 29th falls on a Wednesday.
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 2012 they occurred on:
|Spring Equinox||Tuesday, 20 March 2012.|
|Summer Solstice||Wednesday, 20 June 2012.|
|Fall Equinox||Saturday, 22 September 2012.|
|Winter Solstice||Friday, 21 December 2012.|
The hottest day of 2012 was June 16, with a high temperature of 91°F. For reference, on that day the average high temperature is 85°F and the high temperature exceeds 89°F only one day in ten. The hottest month of 2012 was June with an average daily high temperature of 85°F.
Relative to the average, the hottest day was September 8. The high temperature that day was 89°F, compared to the average of 82°F, a difference of 7°F. In relative terms the warmest month was May, with an average high temperature of 84°F, compared to an typical value of 83°F.
The longest warm spell was from May 12 to May 26, constituting 15 consecutive days with warmer than average high temperatures. The month of May had the largest fraction of warmer than average days with 65% days with higher than average high temperatures.
The coldest day of 2012 was January 15, with a low temperature of 32°F. For reference, on that day the average low temperature is 38°F and the low temperature drops below 36°F only one day in ten. The coldest month of 2012 was January with an average daily low temperature of 37°F.
Relative to the average, the coldest day was March 12. The low temperature that day was 37°F, compared to the average of 49°F, a difference of 11°F. In relative terms the coldest month was November, with an average low temperature of 45°F, compared to an typical value of 49°F.
The longest cold spell was from October 12 to November 7, constituting 27 consecutive days with cooler than average low temperatures. The month of November had the largest fraction of cooler than average days with 93% days with lower than average low temperatures.
The clearest month of 2012 was December, with 71% of days being more clear than cloudy. The longest spell of clear weather was from December 14 to December 30, constituting 17 consecutive days that were clearer than they were cloudy.
The cloudiest month of 2012 was July, with 26% of days being more cloudy than 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 2012 with the most precipitation observations was September 17. There were 13 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 July, with 101 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from November 13 to December 31, constituting 49 consecutive days with no observed precipitation. The month December was completely without observed precipitation.
The month with the largest fraction of days with at least some observed precipitation was July, with 90% of days reporting some observed precipitation.
Either snow is exceptionally rare at this location or this station did not reliably report it during 2012.
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 2012 was March with an average daily low humidity of 23%, and the most humid month was July with an average daily low humidity of 63%.
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 2012, January had 31 dry days, no comfortable days, and no humid days; April had 7 dry days, 23 comfortable days, and no humid days; July had no dry days, no comfortable days, and 31 humid days; and October had no dry days, 28 comfortable days, and 3 humid days.
The highest sustained wind speed was 57 mph, occurring on February 6; the highest daily mean wind speed was 10 mph (March 15); and the highest wind gust speed was 29 mph (June 26).
The windiest month was March, with an average wind speed of 6 mph. The least windy month was December, with an average wind speed of 2 mph.
Visibility is the maximum distance at which a given reference object or light can be clearly discerned. In the United States, visibilities that are greater than or equal to 10 miles are typically reported as 10 miles.
The day of 2012 with the lowest average visibility was January 8, with an average visibility of 1.2 mi. The month with the lowest average visibility was January, with an average visibility of 2.9 mi. With an average visibility of 5.4 mi, the month of August had the highest average visibility.
The cloud ceiling is the altitude of the lowest layer of clouds that are at categorized as broken (mostly cloudy) or overcast (cloudy). If no such cloud layer exists then the ceiling is unlimited and no value is reported.
The day of 2012 with the lowest average cloud ceiling was January 12, with an average cloud ceiling of 49'. The month with the lowest average cloud ceiling was January, with an average cloud ceiling of 5455'. The month of November has the highest average cloud ceiling, with an average cloud ceiling of 17717'.