This report describes the typical weather at the Hangzhou Xiaoshan International Airport (Hangzhou, China) weather station over the course of an average December 21. It is based on the historical records from 1988 to 2012. Earlier records are either unavailable or unreliable.
Hangzhou has a warm humid temperate climate with hot summers and no dry season. The area within 25 mi of this station is covered by croplands (76%), grasslands (9%), oceans and seas (6%), shrublands (6%), and lakes and rivers (2%).
The temperature typically varies from 39°F to 50°F and is rarely below 30°F or above 59°F.
The coolest hours of the day are from 2am to 9am with the coldest at 7am, at which time the temperature is below 44°F three days out of four.
The warmest hours of the day are from noon to 5pm with the hottest at 3pm, at which time the temperature is above 45°F three days out of four.
The day has gained half its heat by 11am and lost it again by 7pm.
On December 21 the Sun rises at 6:51am and sets at 5:03pm.
Solar noon is at 11:57am.
For reference, on the longest day of the year the Sun rises at 4:57am and sets at 7:04pm, while on the shortest day of the year it rises at 6:51am and sets at 5:03pm.
Astronomical twilight begins and ends 85 minutes before sunrise and after sunset at 5:25am and 6:29pm, respectively.
Nautical twilight begins and ends 56 minutes before sunrise and after sunset at 5:55am and 5:59pm, respectively.
Civil twilight begins and ends 26 minutes before sunrise and after sunset at 6:25am and 5:29pm, respectively.
Solar twilight begins and ends 35 minutes after sunrise and before sunset at 7:27am and 4:27pm, respectively.
The median cloud cover ranges from 60% (partly cloudy) to 71% (partly cloudy).
At midnight, the clearest time of the day, the sky is clear, mostly clear, or partly cloudy 46% of the time, and overcast or mostly cloudy 43% of the time.
At 9am, the cloudiest time of the day, the sky is overcast, mostly cloudy, or partly cloudy 55% of the time, and clear or mostly clear 34% of the time.
The sky is typically clearing in earnest by 4pm.
The clouds have typically started forming in earnest by 5am.
There is a 43% chance that precipitation will be observed at some point during the day.
When precipitation does occur it is most often in the form of slight rain (46% of days with precipitation have at worst slight rain) and moderate rain (40%).
Precipitation is observed with more or less equal probability throughout the day.
Either snow is exceptionally unlikely to fall at this location on December 21 or this station does not reliably report precipitation types.
The relative humidity typically ranges from 61% (mildly humid) to 85% (humid), rarely dropping below 33% (comfortable), or exceeding 99% (very humid).
The air is driest at 2pm, at which time the relative humidity is less than 78% (humid) three days out of four; it is most humid at 5am, exceeding 78% (humid) three days out of four.
The dew point ranges from 33°F to 36°F with an average of 35°F.
For reference, comfortable indoor conditions should have a relative humidity between 30% and 50% with a dew point of less than 65°F.
The wind speed is 4 mph (light breeze) on average and is rarely outside the range 1 mph to 8 mph (calm to gentle breeze). The wind speed does not vary substantially during the course of the day.
The wind is most often out of the north (20% of the time) and north west (12% of the time). The wind is least often out of the south east (2% of the time).