Changeable and Rather Wet
Temperatures
The average maximum temperature during July 2021 in Shoreham was 22.5 Celsius (69F), and that was about 1 Celsius (<2F) below normal for the time of year. The average minimum temperature was 14.9 Celsius (59F), and that was slightly above the July average.
The highest temperature recorded during the month was 28.0 Celsius (82F), on the 18th, but 7 other days had maxima above 25 Celsius (77F), including the 20th and 22nd, with both days having highs of 26.7 Celsius (80F). All of these warmer days occurred between the 14th and 23rd. On most days (17) maximum temperatures were between 20 and 25 Celsius (68-77F), but there were a few rather cool days. On 6 occasions maxima were below 20 Celsius (68F), including 3 days with highs under 19 Celsius (66F). There were 4 of these cooler days during the first week of July, but the coolest day was the 10th with a maximum of 18.0 Celsius (64F).
There were no especially warm nights during July, but 16 nights had minimum temperatures above 15 Celsius (59F), including 4 nights with minima above 16 Celsius (61F). All of these warmer nights occurred between the 22nd and 26th, with the highest reading occurring on the 22nd when 16.9 Celsius (62F) was recorded. No particularly cool nights occurred during July, although on 3 occasions minima were below 13 Celsius (55F). On 2 of these cooler nights the temperature dipped below 12 Celsius (54F). The coolest night was the 16th with a minimum of 11.5 Celsius (53F).
The sea temperature was 17 Celsius (63F) at first, but soon rose to 18 Celsius (64F), and for the remainder of the month it varied between 18 and 19 Celsius (64-66F),, although it briefly reached 20 Celsius (68F) at the beginning of the fourth week of July.
Frost
No air frost occurred during July The lowest grass temperature occurred on the 11th when 9.4 Celsius (49F) was recorded.
Rain
Rainfall in July amounted to 64.0 millimetres (2.5 ins.) which was over 30% above the average for the month. Measurable rain fell on 15 days, which was 6 days above the average, and wet days (when 1 millimetre (0.04 ins.) or more of rain falls) numbered 13, and that was 7 days above the average. None of the first 12 days of July were completely dry, although on 4 days there was too little rain to measure, and on most of the other 8 days amounts were small with only 1 day having a total above 4 millimetres (0.15 ins.). That day was the 5th when 19.8 millimetres (0.8 ins.) were recorded. Between the 13th and 22nd no rain occurred, but rain fell late in the evening on the 23rd, and from then until the end of the month there was only 1 completely dry day, and that was the 28th. Amounts of rain were generally small but 4 millimetres (0.15 ins.) were measured on the 23rd, with 15.6 millimetres (0.6 ins.) and 4.8 millimetres (0.2 ins.) falling on the 25th and 26th respectively.
Hail
No hail was observed in this part of Shoreham.
Thunder
There were 4 days when thunder occurred during July. The first storm was heard early in the evening on the 19th. It was quite distant to the northeast and no rain fell. Late in the evening of the 23rd there was thunder and lightning which lasted intermittently into the early hours of the 24th. The last storms of the month occurred on the afternoon of the 31st. Although no rain was recorded in Shoreham, north of the Downs, some torrential bursts were observed, with Steyning measuring over 25 millimetres (1 inch) of rain.
Snow
No sleet or snow was observed this month in Shoreham.
Wind
July was another ‘westerly’ month with winds blowing from the southwest or northwest, accounting for two-thirds of the daily observations. Southwesterlies were dominant with almost half of the days having winds from that quadrant. Although breezes were often light during the second, third and much of the fourth weeks, a few unusually windy days occurred. At Shoreham Airport, the 6th was a windy day with several gusts from between south and southwest reaching 38 knots (43 mph) both in the morning and afternoon. A northeasterly gust of 33 knots (38 mph) occurred in association with thunderstorms in the early hours of the 24th. The 28th was a windy day with afternoon and evening gusts from the southwest reaching 37 knots (42 mph). However, the windiest day of the month was the 30th. In an unusually destructive windstorm for the time of year, southwesterlies gusted over 40 knots (46 mph) with a peak gust of 43 knots (49 mph) early in the afternoon.
Fog
There was early fog on the 2nd, and it stayed quite misty with low cloud until the 4th.
Statistics for July 2021
| Reporting Site | Highest Temp | Lowest Temp | Rain Total (mm) | Wettest | Rain days |
| Shoreham A/P | 26.1 | 9.3 | 44 | 12 | 14 |
| Thorney Island | 26.8 | 9.8 | 92 | 25 | 13 |
| Gatwick A/P | 30.6 | 9.3 | 116 | 23 | 15 |
| Herstmonceux | 29.1 | 11.2 | 83 | 15 | 18 |
| Bournemouth (Hurn) | 29.6 | 8.8 | 107 | 35 | 15 |
| Middle Wallop | 30.6 | 10.1 | 105 | 30 | 13 |
| Dieppe | 26.2 | 11.0 | 68 | 14 | 17 |