Temperatures
The average maximum temperature during September 2020 in Horsholm was 19.2 Celsius, and that was less than 1 degree above normal for the time of year. The average minimum temperature was 9.1 Celsius, and that was a degree below the September normal.
The highest temperature recorded during the month was 26.2 Celsius on the 15th, but 9 other days had maximum temperatures above 20 Celsius, including highs of 24.7 Celsius on the 14th and 23.2 Celsius on the 27th. On many days (13) maximum temperatures were between 16 and 19 Celsius, but there were a couple of cooler days. On the 17th, a high of 15.1 Celsius was recorded, and on the 25th the temperature failed to rise above 14.9 Celsius.
A few mild nights occurred during September, and on 11 nights the minimum temperature was above 10 Celsius. However, only 3 of these milder nights occurred after mid month. The mildest night was the 27th when 15.6 Celsius was recorded, but only 2 other nights had lows above 13 Celsius, the 4th and 14th with 13.8 and 13.3 Celsius respectively. On many nights (13) the minimum temperature was between 7 and 10 Celsius, but there were a few cool nights. On 4 occasions the minimum was under 5 Celsius. The 1st, 17th and 22nd each had minima between 4 and 5 Celsius, but the 18th had a low of 2.9 Celsius, the coldest night of the month.
Frost
No air frost occurred during the month.
Rain
There were 48.6 millimetres of rain during September, and that was about 20% below the monthly average. Rain fell on 13 days, and that was 3 days below average, and wet days, when 1 millimetre or more of rain was measured, amounted to 7 days, and that was also 3 days below average. Although occasional rain fell during the first 24 days of September, daily totals were small with the highest only 3.2 millimetres on the 8th and 2.6 millimetres on the 9th. In fact, between the 13th and 24th less than 1 millimetre of rain was measured. The total for the first 24 days of September was just 13.4 millimetres. Heavy rain fell on the morning of the 25th, causing local flooding, and by the end of the day 24.2 millimetres had fallen. A further 10.2 millimetres fell on the following day, but less than 1 millimetre of rain fell during the last 4 days of the month.
Hail
No hail was observed in this part of Horsholm.
Thunder
No thunder was heard in this part of Horsholm.
Snow
No sleet or snow was observed in this part of Horsholm.
Wind
High pressure was dominant through much of September and winds were less strong than normal. During the first half of the month the southwesterly breezes were quite brisk at times, but very light winds prevailed for most of the third week and the beginning of the fourth week. Thereafter, winds were often from the east, but mainly gentle or moderate in strength.
Fog
Patchy fog was observed overnight during the third week, but none appeared to linger beyond mid morning.