Weather in South London during March 2009
The driest March for 5 years, but generally the month was close to average.
Temperatures
Mean temperatures during March 2009 in Morden were very close to the 20-year normal. The average maximum temperature was 12.7 Celsius (55F), and that was 0.9 degrees Celsius (2F) above normal. The average minimum temperature was 3.4 Celsius (38F), and that was 1.0 Celsius (2F) below normal.
The highest temperature recorded during March was 16.9 Celsius (62F) on the 18th, and there were 4 other days, all between the 15th and 22nd, when maxima exceeded 15 Celsius (59F). There were only 3 days during March when the temperature failed to rise above 10 Celsius (50F); the 4th, 5th and 29th. The coldest day was the 4th with a high of 7.8 Celsius (46F).
The minimum temperature on the night of the 11th/12th was 9.8 Celsius (50F), but there were no other nights when the minimum temperature exceeded 8 Celsius (46F). However, there were 9 further nights with minima above 6 Celsius (43F). On 6 nights the temperature dipped below 0 Celsius (32F), but on only 3 nights were minima below minus 1 Celsius (30F). There was a 3-way tie for the coldest nights, with the 5th/6th, 20th/21st and 29th/30th each recording a low of minus 2.1 Celsius (28F).
Frost
There were 6 air frosts during March, and that's 2 more than average. Only 2 air frosts occurred during the first half of the month, with a further 4 occurring after mid month. There were 14 grass frosts, again, 2 more than average. On 9 nights, the grass minimum fell below minus 3 Celsius (27F) these included 3 nights with values below minus 5 Celsius (23F). The lowest grass minimum occurred on the night of the 5th/6th with a reading of minus 6.7 Celsius (20F).
Rain
A total of 38.1 millimetres (1.5ins) of rain fell during March, and this was only 3% below the long-term average. Measurable rain fell on 13 days, 1 day below average, with the 6 wet days (1.0mm/0.04 ins, or more) 2 days below average. On the 3rd, a total of 18.2 millimetres (0.72 inches) of rain occurred, but the 8th, with 5.1 millimetres (0.2 inches) was the only other day with rainfall exceeding 4 millimetres. No measurable rain fell between the 11th and 22nd inclusive, a total of 12 days.
Thunderstorms
Showers on the 28th produced thunder across south London early in the evening.
Hail
Soft hail (snow pellets) fell in squally showers on the evening of the 8th.
Snow
None reported.
Wind
Winds were generally moderate in strength from between southwest and northwest, but on the evening of the 3rd a strong south to southeasterly wind developed with a gust of 39 knots (44 mph) occurring. An area of high pressure across the country during the third week produced some lighter winds, these becoming east to northeast for a while.
Fog
There was no fog in Morden.
Monthly figures for March in, and around, London
Mean temperatures during March 2009 in Morden were very close to the 20-year normal. The average maximum temperature was 12.7 Celsius (55F), and that was 0.9 degrees Celsius (2F) above normal. The average minimum temperature was 3.4 Celsius (38F), and that was 1.0 Celsius (2F) below normal.
The highest temperature recorded during March was 16.9 Celsius (62F) on the 18th, and there were 4 other days, all between the 15th and 22nd, when maxima exceeded 15 Celsius (59F). There were only 3 days during March when the temperature failed to rise above 10 Celsius (50F); the 4th, 5th and 29th. The coldest day was the 4th with a high of 7.8 Celsius (46F).
The minimum temperature on the night of the 11th/12th was 9.8 Celsius (50F), but there were no other nights when the minimum temperature exceeded 8 Celsius (46F). However, there were 9 further nights with minima above 6 Celsius (43F). On 6 nights the temperature dipped below 0 Celsius (32F), but on only 3 nights were minima below minus 1 Celsius (30F). There was a 3-way tie for the coldest nights, with the 5th/6th, 20th/21st and 29th/30th each recording a low of minus 2.1 Celsius (28F).
Frost
There were 6 air frosts during March, and that's 2 more than average. Only 2 air frosts occurred during the first half of the month, with a further 4 occurring after mid month. There were 14 grass frosts, again, 2 more than average. On 9 nights, the grass minimum fell below minus 3 Celsius (27F) these included 3 nights with values below minus 5 Celsius (23F). The lowest grass minimum occurred on the night of the 5th/6th with a reading of minus 6.7 Celsius (20F).
Rain
A total of 38.1 millimetres (1.5ins) of rain fell during March, and this was only 3% below the long-term average. Measurable rain fell on 13 days, 1 day below average, with the 6 wet days (1.0mm/0.04 ins, or more) 2 days below average. On the 3rd, a total of 18.2 millimetres (0.72 inches) of rain occurred, but the 8th, with 5.1 millimetres (0.2 inches) was the only other day with rainfall exceeding 4 millimetres. No measurable rain fell between the 11th and 22nd inclusive, a total of 12 days.
Thunderstorms
Showers on the 28th produced thunder across south London early in the evening.
Hail
Soft hail (snow pellets) fell in squally showers on the evening of the 8th.
Snow
None reported.
Wind
Winds were generally moderate in strength from between southwest and northwest, but on the evening of the 3rd a strong south to southeasterly wind developed with a gust of 39 knots (44 mph) occurring. An area of high pressure across the country during the third week produced some lighter winds, these becoming east to northeast for a while.
Fog
There was no fog in Morden.
Monthly figures for March in, and around, London
| Place | Maximum | Minimum | Rainfall (mm) |
| C. London | 17.2 | 2.0 | 32 |
| Heathrow A/P | 16.6 | -0.4 | 31 |
| Gatwick A/P | 16.2 | -2.9 | 45 |
| Croydon | 13.7 | -1.8 | 47 |
| Northolt | 16.4 | -2.7 | 36 |
| Farnborough | 15.5 | -3.9 | 34 |
| Stansted A/P | 15.4 | -3.6 | 40 |