Very Wet
Temperatures
The average maximum temperature during September 2024 in Shoreham was 19.7 Celsius (68F), and that was around 1 Celsius (1.8F) above the long-term average, but nearly 1 degree Celsius (1.8F) below the average for the last 10 years. In fact, average day-time temperatures this September were the 29th highest in the area since 1880, but it was also the coolest September for 6 years. The average minimum temperature was 12.4 Celsius (54F), and that was around 1 Celsius (<2F) above the long-term September normal, but near normal compared with short-term averages.
The highest temperature recorded during the month was 29.3 Celsius (85F) on the 1st, but the second highest was only 25.0 Celsius (77F) on the 19th. A further 2 days had maxima over 23 Celsius (73F). Both the 20th and 21st had a high of 23.9 Celsius (75F). There were 2 rather warm spells in September. From the 1st to 4th inclusive, and from the 18th and 21st inclusive, temperatures rose above 20 Celsius (68F). Just 1 other day, the 8th, with a high of 20.9 Celsius (70F), had a maximum temperature above 20 Celsius (68F). Most other maxima ranged from 15 to 20 Celsius (59-68F), On 5 of these cooler days the temperature failed to rise above 17 Celsius (63F), including the last 3 days of the month. There was just 1 day, the 27th, when the temperature stayed below 15 Celsius (59F). On that day, the temperature peaked at 13.7 Celsius (57F).
There were several warm nights during September, these mainly occurred during the first and third weeks of the month. On the 2nd, a minimum of 18.3 Celsius (65F) occurred, with 17.0 Celsius (63F) recorded on the following night. A further 6 nights had lows above 15 Celsius (59F), including the 1st, 19th and 22nd with lows of 16.6, 16.5 and 16.1 Celsius (62-61F) respectively. On most other nights the minimum temperature ranged from 10 to 15 Celsius (50-59F). There were 8 exceptions. Both the 28th and 29th had minima of 6.9 Celsius (45F), but all the other cool nights occurred between the 10th and 15th. Only 2 of these nights had a temperature below 7 Celsius (45F). A minimum of 5.9 Celsius (43F) was measured on the 13th, but the coolest night of the month was the 14th, when 4.7 Celsius (40F) was recorded.
The sea temperature was 19 or 20 Celsius (66-68F) at the beginning of September, but fell to 18 Celsius (64F) during the second week, and to 17 Celsius (63F) at times during the last week of the month.
Frost
There were no frosts in September. The lowest grass temperature was 1.1 Celsius (34F), on the 14th.
Rain
Rainfall in September amounted to 158.3 millimetres (6.2 ins.), which was around 2.5 times the monthly average. Locally, it appears to be the 4th wettest September since records began in 1880. In recent years, the Septembers of 1976 and 1999 had comparable amounts of rain, but the Septembers of both 1974 and 1975 were both wetter. Measurable rain fell on 18 days, which was 6 days above the average, and wet days (when 1 millimetre (0.04 ins.), or more, of rain falls) numbered 13, which was also 6 days above the average. Although the 1st was dry during the day, rain fell overnight, and further rain fell during the 2nd leading to a total for the day of 6.8 millimetres (0.27 ins.). Heavy rain fell at times on both the 5th and 6th, leading to daily totals of 25.4 millimetres (1 in.) and 11.2 millimetres (0.44 ins.) respectively. Thereafter, rainfall was less intense for a while. Although 4.6 millimetres (0.18 ins.) of rain fell on the 10th, the period between the 7th and 19th only yielded 7.4 millimetres (0.29 ins.) of rain. In fact, no measurable rain fell between the 12th and 19th. Rain returned on the night of the 20th, and, at times, it was heavy. A total of 9.6 millimetres (0.38 ins.) on the 21st, was followed by 13.8 millimetres (0.54 ins.) on the 22nd. Worse was to follow, as a fall of 7.8 millimetres (0.31 ins.) on the 25th was followed by a very wet day and night on the 26th. The total for the day was 41.4 millimetres (1.63 ins.). This was one of the heaviest daily falls in recent years, but there was still more to come. Heavy overnight rain on the 29th/30th produced a further 21.3 millimetres (0.84 ins.) of rain.
Hail
No hail was observed in this part of Shoreham during the month.
Thunder
There were 3 days when thunderstorms occurred during September. On the 5th, there was thunder at times from early to mid afternoon. Showery outbreaks of rain were accompanied by thunder after dawn on the 6th; and lightning and thunder occurred in the early hours of the 21st.
Snow
No sleet or snow was observed in Shoreham.
Wind
September was the first month this year that was not a ‘southwesterly month’. Winds from that direction only accounted for around 15% of the daily observations. Northwesterly predominated, but only with around 35% of the monthly total. Northeasterly winds occurred on over 25% of the days, with the remaining days of the month having variable winds. Overall, winds were lighter than in an average September, with the lightest winds occurring at the beginning of the month, and for much of the third week. At Shoreham Airport, the only really windy day was the 26th. Southwesterly gusts peaked at 41 knots (47 mph) during the middle of the afternoon, followed by westerly winds that reached 35 knots (40 mph) in the early hours of the 27th. On the evening of the 29th, southeasterly winds exceeded 30 knots (34 mph) on several occasions, before veering south to southwesterly overnight. Highest gusts, spanning midnight, were 32 or 33 knots (36-38 mph).
Fog
No fog was observed in this part of Shoreham during the month.
Statistics for September 2024
| Reporting Site | Highest Temp | Lowest Temp | Rain Total (mm) | Wettest | Rain days |
| Shoreham A/P | 28.8 | 4.1 | 18 | ||
| Thorney Island | 28.5 | 4.6 | 18 | ||
| Gatwick A/P | 27.8 | 1.7 | 18 | ||
| Herstmonceux | 29.6 | 3.6 | 19 | ||
| Bournemouth (Hurn) | 26.2 | 0.7 | 20 | ||
| Middle Wallop | 26.9 | 3.0 | 20 | ||
| Dieppe | 24.7 | 4.8 | 109 | 44 | 18 |
- Rainfall totals unreliable for all English stations