Another mild and changeable month

Temperatures

The average maximum temperature during December 2018 in Shoreham was 10.2 Celsius (50F), and that was around 2 degree Celsius (3.5F) above normal for the time of year. The average minimum temperature was 6.4 Celsius (44F), and that was  about 2.5  degrees Celsius (4F) above the December normal.   

The highest temperature recorded during the month was 13.5 Celsius (56F) on the 3rd, but the 2nd was also very mild with a high of 13.2 Celsius (56F).  There were 5 further days with highs above 12 Celsius (54F), and in total there were 17 days during December when the temperature exceeded 10 Celsius (50F).  The first 10 days of the month only had 1 day when the temperature failed to reach 10 Celsius (50F). The following 10 days only  had 2 occasions with maxima above 10 Celsius (50F). Less mild days also occurred between the 24th and 28th. However, in total, only 4 days had maxima below 8 Celsius (46F). The consecutive days, 12th, 13th and 14th had highs of 7.9 Celsius (46F), 5.7 Celsius (42F) and 3.9 Celsius (39F) respectively; and the 27th had a maximum of 6.7 Celsius (44F).

There were many mild nights during December, especially during the first week. On 4 occasions, all of these during the first week, the temperature remained above 10 Celsius (50F). On 3 of these mild nights the temperature stayed above 11 Celsius (52F), and included a low of 12.1 Celsius (54F) on the 2nd. Although there were only another 5 nights with lows above 8 Celsius (46F), there were further 10 nights with minima between 5 and 8 Celsius (41-46F). No particularly cold nights occurred during December, but on 6 occasions minima were lower than 3 Celsius (37F). However, the temperature only dipped below 1 Celsius (34F) twice. On the 28th there was a low of 0.9 Celsius (34F), but the coldest night of the month was the 14th with a minimum of 0.1 Celsius (32F). 

The sea temperature slowly decreased from 11 Celsius (52F) at the beginning of the month to 9 Celsius (48F) by the end of December.

Frost

There were no air frosts during December, but 7 grass frosts occurred. There were 2 grass frosts during the first week, a further 4 between the 11th and 17th, but only 1 after the 17th. The grass temperature only fell below minus 2 Celsius (28F) twice. On the 14th there was a minimum of minus 3.3 Celsius (26F), with minus 2.2 Celsius (28F) recorded on the 16th.   

Rain

There were 84.2  millimetres (3.3 ins.) of rain during December and that was slightly above the monthly average. There were 16 days of measurable rain, and that was normal for December. The first week was very changeable, with measurable rain on each of the first 8 days of December. Daily totals included 6.8 millimetres (0.3 ins.) on the 1st and 5.2 millimetres (0.2 ins.) on the 6th. No measurable rain fell between the 9th and 14th, but spells of heavy on the 15th gave 21.4 millimetres (0.8 ins.), making it the wettest day of the month. It stayed very unsettled until the 23rd, with heavy showers, or longer spells of rain, giving further high daily totals. On the 18th, there were 13.6 millimetres (0.5 ins.) recorded, with 7.2 millimetres (0.3 ins.) on the 19th, and 6.2 millimetres (0.25 ins.) on the following day. By way of a contrast, no measurable rain fell on the last  8 days of December.

Hail

There was no hail observed in this part of Shoreham during December.

Thunder

There was no thunder heard in this part of Shoreham during December.

Snow

There was no snow or sleet in Shoreham during December.

Wind

Apart from some rather chilly winds from between southeast and northeast at the end of the second week, and for a while around Christmas, the winds were predominately from between southwest and northwest. Pressure was well above the December average, even so, there were spells with strong winds, especially at the beginning of the second week, and again around the end of the third week.  At Shoreham Airport, southwesterly gusts reached 30 knots  (34 mph) on the afternoons of both the 2nd and 3rd, with 36 knots (41 mph) recorded on the morning of the 7th. It stayed windy, and 38 knots (43 mph) occurred on the afternoon of the 8th.  Gusts exceeded 30 knots (34 mph) again on the morning of the 13th and on the evening of the 15th. The 18th and 20th were both windy, and in the early hours of the 20th there was a gust  of 38 knots (43 mph). For the remainder of December winds were generally much lighter.    

Fog

No fog was observed in this part of Shoreham, although it was very misty early on the 30th.

Statistics for December 2018