Cloudy and Wet
Temperatures
The average maximum temperature during December 2020 in Horsholm was 5.6 Celsius, and that was around 0.5 degrees below normal for the time of year. The average minimum temperature was 2.8 Celsius, and that was close to 1 degree above the December normal.
The highest temperature recorded during the month was 8.4 Celsius on the 22nd, with 8.1 Celsius recorded on the 6th, and 8.0 Celsius on the 18th. There were a further 5 days with maxima above 7 Celsius, including 3 consecutive days beginning on the 15th. No particularly cold days occurred during December, but on 12 days the maximum temperature was below 5 Celsius. The coldest days were the 11th and 25th, with both having a maximum temperature of 2.9 Celsius. The only other maximum below 4 Celsius occurred on the 26th, when 3.8 Celsius, although each of the last 9 days of December had maxima below 5 Celsius.
Several mild nights occurred during December, and on 6 occasions the temperature stayed above 5 Celsius. The third week of the month had most of the milder nights, with 4 nights between the 16th and 21st having minima above 5 Celsius. However, the mildest nights were the 7th and 14th, with 6.2 and 6.5 Celsius respectively. December was an unusually cloudy month. In fact, the sun only appeared on 6 days in Copenhagen, and just 3 days in Roskilde. The cloudy nights generally prevented temperatures from falling particularly low, especially early in the month. Of the 10 nights when the temperature fell below 2 Celsius, only 2 of these colder nights occurred before the 23rd. The lowest temperatures occurred on the 25th and 26th, with minima of minus 3.3 and minus 4.2 Celsius respectively.
Frost
Only 2 air frosts occurred in December, and that’s 6 below the average. However, on 5 nights the temperature dipped to between 0 and 1 Celsius. All of these low temperatures, except 1, occurred between the 23rd and 28th, with the exception being on the 3rd, when a minimum temperature of 0.7 Celsius was recorded.
Rain
There were 64.8 millimetres of rain recorded during December and that was around 40% above the average. Rain fell on 22 days, and that was 2 days above average, and wet days (when 1 millimetre or more of rain was measured) numbered 14 days, and that was also 2 days above average. In an unsettled month, much of the rain was light and drizzly, but on the 6th, a total of 11.2 millimetres were measured, making it the wettest day of the month. On 15th there was a further 7 millimetres of rain, with 5.8 millimetres on the 17th, another 10.4 millimetres on the 27th, and 5.8 millimetres again on the 31st.
Hail
No hail was observed in this part of Horsholm.
Thunder
No thunder was heard in this part of Horsholm.
Snow
Light sleet fell on the afternoon of the 3rd, with sleet and wet snow late in the afternoon and during the evening of the 27th, but the snow did not settle.
Wind
December was a month of southeasterly winds, with this direction accounting for more than half of the monthly observations. On most other days the wind blew from between south and southwest. The southwest wind was particularly strong on the 26th, and the southeasterly even stronger on the 27th, otherwise on most days the wind was moderate or fresh, with only 4 days when the average wind could be considered as being light.
Fog
Although several days were quite misty, no fog was present at the time of the morning observation.