Weather in South London during October 2009
Mild and dry. The driest October for 6 years.
Temperatures
The average maximum temperature during October 2009 was 16.1 Celsius (61F), and that was 0.5 Celsius (1F) above the 20-year normal, but 1.3 degrees Celsius (2F) above the 100-year normal. The average minimum temperature was 8.5 Celsius (48F), and that was 0.3 Celsius (0.5F) above the 20-year average, and 1.1 Celsius above the 100-year normal.
The highest temperature recorded during October was 19.8 Celsius (68F) on the 6th, but there were 5 other days when 18 Celsius (64F) was reached, including the last day of the month. The coolest days were just after mid month and on both the 17th and 18th maxima of 12.5 Celsius were recorded. The lengthiest spell of mild weather occurred late in the month, and each of the last 9 days had highs of 16 Celsius (61F) or more.
There were no very mild nights during October, although the minimum on the night of the 5th/6th was 13.2 Celsius (56F).There were 13 nights when the temperature stayed above 10 Celsius (50F), but only 2 of these milder nights occurred between the 12th and 23rd. On 5 nights the air temperature fell below 5 Celsius (41F), and on the night of 12th/13th a low of 2.1 Celsius (36F) occurred. However, the coldest night was the 17th/18th with a minimum of minus 0.8 Celsius (31F).
Frost
There was 1 air frost during October, the night of the 17th/18th, and there were 3 grass frosts. The lowest grass minimum was minus 5.1 Celsius (23F), this occurring on the same night as the air frost.
Rain
A total of 34.8 millimetres (1.4ins) of rain fell during October, and that was only around 50% of average. Measurable rain fell on 15 days, the average October number, and there were 8 wet days (1.0mm/0.04 ins, or more) and that was 2 days below average. The wettest day was the 7th with 14.6 millimetres (0.6 ins) and the 5th, with 6.2 millimetres, was the only other day when more than 3 millimetres of rain was recorded. After the 7th, the total rainfall for the rest of October was less than 10 millimetres (0.4 ins). although during that period there were never more than 3 consecutive completely dry days.
Thunderstorms
For the 3rd consecutive month no thunderstorms were observed in this part of London.
Hail
No hail was observed in this part of South London.
Snow
None reported.
Wind
Gentle or moderate winds from between southwest and northwest predominated during October, although light or gentle east to southeast breezes occurred on several days, mainly during the third and fourth weeks. Remarkably, gusts only exceeded 20 knots (23mph) on 6 days. The highest gust was 26 knots (30mph) from the west on the 3rd.
Fog
None reported in this part of London.
Monthly figures for October in, and around, London
The average maximum temperature during October 2009 was 16.1 Celsius (61F), and that was 0.5 Celsius (1F) above the 20-year normal, but 1.3 degrees Celsius (2F) above the 100-year normal. The average minimum temperature was 8.5 Celsius (48F), and that was 0.3 Celsius (0.5F) above the 20-year average, and 1.1 Celsius above the 100-year normal.
The highest temperature recorded during October was 19.8 Celsius (68F) on the 6th, but there were 5 other days when 18 Celsius (64F) was reached, including the last day of the month. The coolest days were just after mid month and on both the 17th and 18th maxima of 12.5 Celsius were recorded. The lengthiest spell of mild weather occurred late in the month, and each of the last 9 days had highs of 16 Celsius (61F) or more.
There were no very mild nights during October, although the minimum on the night of the 5th/6th was 13.2 Celsius (56F).There were 13 nights when the temperature stayed above 10 Celsius (50F), but only 2 of these milder nights occurred between the 12th and 23rd. On 5 nights the air temperature fell below 5 Celsius (41F), and on the night of 12th/13th a low of 2.1 Celsius (36F) occurred. However, the coldest night was the 17th/18th with a minimum of minus 0.8 Celsius (31F).
Frost
There was 1 air frost during October, the night of the 17th/18th, and there were 3 grass frosts. The lowest grass minimum was minus 5.1 Celsius (23F), this occurring on the same night as the air frost.
Rain
A total of 34.8 millimetres (1.4ins) of rain fell during October, and that was only around 50% of average. Measurable rain fell on 15 days, the average October number, and there were 8 wet days (1.0mm/0.04 ins, or more) and that was 2 days below average. The wettest day was the 7th with 14.6 millimetres (0.6 ins) and the 5th, with 6.2 millimetres, was the only other day when more than 3 millimetres of rain was recorded. After the 7th, the total rainfall for the rest of October was less than 10 millimetres (0.4 ins). although during that period there were never more than 3 consecutive completely dry days.
Thunderstorms
For the 3rd consecutive month no thunderstorms were observed in this part of London.
Hail
No hail was observed in this part of South London.
Snow
None reported.
Wind
Gentle or moderate winds from between southwest and northwest predominated during October, although light or gentle east to southeast breezes occurred on several days, mainly during the third and fourth weeks. Remarkably, gusts only exceeded 20 knots (23mph) on 6 days. The highest gust was 26 knots (30mph) from the west on the 3rd.
Fog
None reported in this part of London.
Monthly figures for October in, and around, London
| Place | Maximum | Minimum | Rainfall (mm) |
| C. London | 20.2 | 6.7 | 27 |
| Heathrow A/P | 20.0 | 3.3 | 43 |
| Gatwick A/P | 18.7 | -1.1 | 42 |
| Croydon | 17.8 | 0.8 | 35 |
| Northolt | 19.5 | 0.1 | 40 |
| Farnborough | 19.0 | -1.2 | 47 |
| Stansted A/P | 19.3 | 2.7 | 38 |