Extremely Wet, Windy and Rather Cool
Temperatures
The average maximum temperature during October 2020 in Shoreham was 15.3 Celsius (60F), and that was about 0.5 Celsius (<1F) below normal for the time of year. The average minimum temperature was 9.3 Celsius (49F), and that was less than 0.5 Celsius (<1F) below the October normal.
The highest temperature recorded during the month was 19.0 Celsius (66F) on the 8th, but there were only 4 other days with maxima above 17 Celsius (63F). On the 20th the temperature reached 17.5 Celsius (63F), with the other 3 warmer days occurring in the first week of October. On most days (20) the temperature rose to between 14 and 17 Celsius (57-63F), but a few cooler days occurred. The coolest day of the month was the 4th with a high of 12.1 Celsius (54F), however, on 3 other occasions the maximum was below 13 Celsius (55F), on the 13th, 16th and 25th. The coolest of these 3 days was the 13th with a high of 12.3 Celsius (54F).
No warm nights occurred during October, but on both the 21st and 30th a minimum of 14.3 Celsius (58F) occurred, and on 4 other nights, the 8th, 20th, 22nd and 31st, minimum temperatures were above 13 Celsius (55F). However, there were only 2 other nights with minima above 10 Celsius (50F). On several nights (11), the temperature fell to between 8 and 10 Celsius (46-50F), with a further 8 nights having lows between 5 and 8 Celsius (41-46F). The only night with a minimum below 5 Celsius (41F) was the 10th when 4.1 Celsius (39F) was measured..
The sea temperature was around 16 Celsius (61F) at the beginning of October, falling slowly to 13 or 14 Celsius (55-57F) by the end of the month.
Frost
No air frost occurred during October, but on the 10th there was a grass frost with a minimum temperature of minus 0.6 Celsius (31F).
Rain
Rainfall in October amounted to 232.2 millimetres (9.1 ins.). This was more than 4 times the monthly average. In the last 140 years there have only been 2 Octobers with rainfall totals approaching those of 2020, namely 1987 and 2000. In October 2000, although totals were higher north of the South Downs, around Shoreham values were 40 or 50 millimetres (<2 ins.) lower. In October 1987, several sites near Shoreham had totals higher than those of October 2020, but the closest site, around 1 kilometre away, had 226 millimetres (8.9 ins.). Rain fell on 24 days, which is 7 days above average, and wet days (when 1 millimetre (0.04 ins.) or more of rain falls) numbered 20 days, and that was 9 days above average. The month began with one of the heaviest rainfall events for several decades. The total rainfall between the 30th September and 4th October (5 days) was 127.4 millimetres (5 ins.). It included 18.4 millimetres (0.7 ins.) on the 1st, a massive 52.4 millimetres (2.1 ins.) on the 2nd, and 19.8 millimetres (0.8 ins.) on the 3rd. Nationally, the 3rd was the wettest day since records began in 1891 with 7.6 cubic kilometres of rain falling, which, when spread across the nation, is the equivalent of 35 millimetres (1.4 ins.) measured from every rain-gauge in the country. On the 4th, a further 14.2 millimetres (0.56 ins.) were recorded, and although daily totals stayed below 3 millimetres (0.1 ins.) the first dry day was not until the 11th. On the 12th, over 10 millimetres (0.4 ins.) of rain fell, but then a respite occurred with no significant rain measured between the 14th and 18th, but only 1 more dry day occurred after the 18th, and that was the 22nd. Between the 20th and the end of the month, there were 7 days with rainfall above 5 millimetres (0.2 ins.), including 4 days with totals exceeding 10 millimetres (0.4 ins.). the wettest days were the 24th with 26.0 millmetres (1 in.) and the 25th when 19.2 millimetres (0.8 ins.) were measured.
Hail
Small hail fell briefly mid-evening on the 25th.
Thunder
No thunder was heard during October.
Snow
No sleet or snow fell during October.
Wind
October was frequently windy with only the third week having a short lull from the predominantly westerly winds. Southwesterly and northwesterly winds were almost equally divided and between them accounted for over 60% of the daily observations. Winds with an easterly component mainly occurred around mid-month when areas of high pressure transited the country. At Shoreham Airport, southwesterly gusts reached 38 knots (43 mph) with gusts to 32 knots (37 mph), again from the southwest, in the early hours and the afternoon. of the 6th. The 8th was breezy in the morning, and gusts from the southwest peaked at 33 knots (38 mph) early in the afternoon. The next time gusts exceeded 30 knots (34 mph) was not until the 24th. On that day, strong south to southwesterly winds increased in the afternoon, and during the evening a gust of 44 knots (50 mph) was measured. The strong winds continued into the morning of the 25th when 31 knots (35 mph) were recorded. South to southwest winds were strong on the afternoon of the 27th with the highest gust of 36 knots (41 mph). The 28th was windy throughout the day with a top gust, from the southwest, of 33 knots (38 mph). The remainder of the month stated breezy, and on the afternoon gusts exceeded 30 knots (34 mph). The highest was 35 knots (40 mph).
Fog
There was no fog observed in this part of Shoreham during October.
Statistics for October 2020
| Reporting Station | Highest Temp | Lowest Temp | Rain Total (mm) | Wettest | Rain days |
| Shoreham A/P | 18.7 | 3.5 | 192 | 38 | 24 |
| Thorney Island | 18.7 | 5.6 | 160 | 33 | 23 |
| Gatwick A/P | 17.7 | 2.3 | 169 | 35 | 24 |
| Herstmonceux | 18.3 | 4.6 | 201 | 35 | 25 |
| Bournemouth (Hurn) | 18.6 | 1.5 | 170 | 26 | 24 |
| Middle Wallop | 17.1 | 4.0 | 181 | 37 | 23 |
| Dieppe | 19.5 | 6.2 | 108 | 22 | 26 |