Dry and Anticyclonic
Temperatures
The average maximum temperature during March 2021 in Shoreham was 11.6 Celsius (53F), and that was about 1 Celsius (<2F) above normal for the time of year. The average minimum temperature was 4.2 Celsius (40F), and that was around 0.5 Celsius (<1F) below the March normal.
The highest temperature recorded during the month was 19.6 Celsius (67F), on the 30th, and on the 31st a maximum of 18.5 Celsius (65F) occurred. However, the only other day with a temperature above 15 Celsius (59F) was on the 16th, when 15.1 Celsius (59F) was measured. On most days, the temperature rose to between 10 and 15 Celsius (50-59F) but there were a few cool days, mainly during the first week of March. On 7 occasions the temperature failed to reach 10 Celsius (50F), but the only cool day after mid-month was the 18th with a high of 9.8 Celsius (50F). A cluster of cool days occurred between the 4th and the 8th, and although the 5th and 7th both had maxima below 8 Celsius (46F), the 4th, with a maximum of 6.4 Celsius (44F), was the only day when the temperature was under 7 Celsius (45F).
No particularly mild nights occurred during March, but the temperature only fell to 9.0 Celsius (48F) on the 11th, and there were minima of 8.7 Celsius (48F) on the 26th and 8.6 Celsius (47F) on both the 28th and 29th. However, there were only 4 other nights when the temperature stayed above 6 Celsius (43F). On many nights (11), the minima were between 2 and 4 Celsius (36-39F), but some colder nights occurred. On the 7th a low of minus 0.6 Celsius (31F) occurred, with minus 2.6 Celsius (27F) was measured. After the 9th, the only temperature below 2 Celsius (36F) was the low of 0.3 Celsius (32F) recorded on the 20th.
The sea temperature was around 7 Celsius (45F) at the beginning of March, before slowly rising to 8 Celsius (46F), and then to 9 Celsius (48F) on the last 2 days of the month.
Frost
Air frost occurred on 2 nights during March, and that was average for the time of year. However, there were 17 grass frosts, and that was 8 more than can be expected in a normal March. No prolonged period was free of grass frost during March, with 3 consecutive days, beginning on the 3rd, the longest spell. On each night between the 6th and 10th, and again between the 22nd and 25th, grass frost occurred, but on many nights throughout the month, frost was slight. On 7 nights the grass temperature dipped below minus 3 Celsius (27F), but the only night with a minimum below minus 5 Celsius (23F) was on the 8th when minus 7.2 Celsius (19F) was measured.
Rain
Rainfall in March amounted to 30.6 millimetres (1.2 ins.). This was about 50% of the monthly average. Rain fell on 10 days, which is 8 days below average, and wet days (when 1 millimetre (0.04 ins.) or more of rain falls) numbered 6 days, and that was 6 days below average. The month began cloudless, but rain on the 3rd amounted to 3.4 millimetres (0.13 ins.). No measurable rain fell between the 4th and the 9th, but during an unsettled spell that lasted around a week, the bulk of the month’s rain fell. On the 10th, a total of 9 millimetres (0.35 ins.) was measured, and the 12th, with 11.2 millimetres (0.44 ins.), was the wettest day of the month. After the 11th, rain was sporadic and mostly light. The largest amount was 2 millimetres (0.08 ins.) on the 25th, and between the 13th and the end of the month (19 days) less than 7 millimetres (0.25 ins.) of rain fell.
Hail
Small hail briefly fell in heavy showers late in the afternoon and early in the evening on the 12th.
Thunder
No thunder was heard in this part of Shoreham.
Snow
No sleet or snow fell in this part of Shoreham.
Wind
Although the mean sea level pressure readings were much higher than average (around 11 millibars on the barometer), the winds were often quite strong, especially during the second and last weeks of March. There was no dominant direction, with the daily readings equally divided between southwest and northeast, with several days having winds from the northwest. At Shoreham Airport, southwesterly gusts reached 35 knots (40 mph) on the evening of the 10th, and squally southwesterly gusts peaked at 45 knots (51 mph) in the early hours of the 11th. The strong southwest winds continued through the rest of the day, and into the 12th and 13th. A gust of 33 knots (38 mph) occurred on the afternoon of the 12th, with 42 knots (48 mph) recorded on the morning of the 13th. Lighter winds then prevailed until the 26th when a southwesterly gust of 32 knots (36 mph) was registered. Although breezy on the 28th, no further gusts above 30 knots (32 mph) were reported during March.
Fog
Both the 2nd and 3rd were very misty at times, but no fog was reported at the time of the morning observation (0900 UTC).
Statistics for March 2021
| Reporting Site | Highest Temp | Lowest Temp | Rain Total (mm) | Wettest | Rain days |
| Shoreham A/P | 16.6 | -3.9 | 21 | 6 | 13 |
| Thorney Island | 17.4 | -4.2 | 21 | 13 | 10 |
| Gatwick A/P | 23.0 | -5.3 | 39 | 10 | 14 |
| Herstmonceux | 20.8 | -3.4 | 36 | 8 | 14 |
| Bournemouth (Hurn) | 20.2 | -5.0 | 35 | 10 | 14 |
| Middle Wallop | 21.8 | -1.2 | 39 | 9 | 13 |
| Dieppe | 23.8 | -0.5 | 31 | 5 | 16 |