Weather in South London during January 2009
Cold and rather wet, with a cold start to the year, and a very wet period after mid month.
Temperatures
Temperatures during January 2009 in Morden were well below the 20-year average, making it the coldest January for 12 years, and before that the Januaries of both 1985 and 1987 were colder.. The average maximum was 6.5 Celsius (44F), and that was 1.9 degrees Celsius (3F) below normal. The average minimum temperature was 1.0 Celsius (34F), and that was 2.6 Celsius (5F) below normal.
The highest temperature recorded in January was only 10.5 Celsius (51F) on the 22nd, and this was the lowest monthly maximum for January since 1979. There were 4 other days with highs above 10 Celsius (50F), the 12th, 13th, 17th and 26th. The coldest days occurred early in the month, with 8 out of the first 10 days having maxima below 5 Celsius (41F). The 14th was the only other day during January with a maximum below 5 Celsius. On the 4th, the temperature only rose to 0.8 Celsius (33F), but the coldest day of the month was the 10th, when a dull and misty day was accompanied by a high of just minus 0.7 Celsius (31F).
There were only 4 nights when the temperature remained above 5 Celsius (41F), the 11th/12th, 12th/13th, 16th/17th and 21st/22nd. The mildest night was the 11th/12th with a low of 7.9 Celsius (46F). Only 3 out of the first 11 nights of January had minima above freezing, and on 3 occasions the temperature fell below minus 5 Celsius (23F). The coldest night was the 5th/6th when a minimum of minus 6.4 Celsius (20F) was recorded.
Frost
There were 12 air frosts in January, and that's 6 more than average. A total of 8 air frost occurred during the first 11 days. There were 18 grass frosts, exceeding the average by 5. Grass temperatures fell below freezing on the first 11 nights of the year, and there were 9 nights with values below minus 5 Celsius (23F), including the nights of the 20th/21st and 23rd/24th. After a low of minus 9 Celsius (16F) on the night of the 5th/6th, the minimum on the following night was minus 10 Celsius (14F).
Rain
A total of 69.5 millimetres (2.7 ins) of rain fell during January, and this was 25% above the long-term average. Measurable rain fell on 15 days, 2 below average, but the 13 wet days (1.0mm/0.04 ins, or more) were 3 days above average. The first fortnight of January only yielded 3.9 millimetres (0.15 inches), but from the 16th to the 24th over 56 millimetres (2.2 ins) was recorded. This included falls of 13 millimetres (0.5 ins) on the 18th, a total of 16.8 millimetres (0.66 ins) on the 22nd, with another 11.6 millimetres falling on the 24th.
Thunderstorms
No thunderstorms were reported.
Hail
Soft hail (snow pellets) fell early in the afternoon on the 5th, with small hail falling as a squally trough passed through at 0040 hours on the 18th. Another soft hail shower occurred at 0017 hours on 20th.
Snow
Light snow fell in the early hours of the 5th. Although it turned to freezing drizzle for a while, a total of 1 centimetre was measured at 0900 hours. Further light snow occurred after mid morning with a ligh snow shower early in the afternoon. Most of the snow had disappeared by evening but thin patches persisted until the 11th. A light flurry of snow occurred before dawn on the 7th, but the only other wintery precipitation that occurred was on the 23rd when rain briefly turned to sleet around 1000 hours.
Wind
Winds were mainly light or gentle east to northeast during the cold spell early in the month, although a moderate northeasterly blew on the 5th. Around the middle of the second week, the winds became southwesterly and for the remainder of the month the direction mostly fluctuated between southeast and southwest. A fresh southwesterly blew on the 11th, and strong southerly winds produced a gust of 44 knots (50 mph) on the 17th. Generally, though the breezes were gentle or moderate, and during the last week occasionally light.
Fog
There was freezing fog very early on the 10th, and on the 14th there was a morning of fog, dense at times.
Temperatures during January 2009 in Morden were well below the 20-year average, making it the coldest January for 12 years, and before that the Januaries of both 1985 and 1987 were colder.. The average maximum was 6.5 Celsius (44F), and that was 1.9 degrees Celsius (3F) below normal. The average minimum temperature was 1.0 Celsius (34F), and that was 2.6 Celsius (5F) below normal.
The highest temperature recorded in January was only 10.5 Celsius (51F) on the 22nd, and this was the lowest monthly maximum for January since 1979. There were 4 other days with highs above 10 Celsius (50F), the 12th, 13th, 17th and 26th. The coldest days occurred early in the month, with 8 out of the first 10 days having maxima below 5 Celsius (41F). The 14th was the only other day during January with a maximum below 5 Celsius. On the 4th, the temperature only rose to 0.8 Celsius (33F), but the coldest day of the month was the 10th, when a dull and misty day was accompanied by a high of just minus 0.7 Celsius (31F).
There were only 4 nights when the temperature remained above 5 Celsius (41F), the 11th/12th, 12th/13th, 16th/17th and 21st/22nd. The mildest night was the 11th/12th with a low of 7.9 Celsius (46F). Only 3 out of the first 11 nights of January had minima above freezing, and on 3 occasions the temperature fell below minus 5 Celsius (23F). The coldest night was the 5th/6th when a minimum of minus 6.4 Celsius (20F) was recorded.
Frost
There were 12 air frosts in January, and that's 6 more than average. A total of 8 air frost occurred during the first 11 days. There were 18 grass frosts, exceeding the average by 5. Grass temperatures fell below freezing on the first 11 nights of the year, and there were 9 nights with values below minus 5 Celsius (23F), including the nights of the 20th/21st and 23rd/24th. After a low of minus 9 Celsius (16F) on the night of the 5th/6th, the minimum on the following night was minus 10 Celsius (14F).
Rain
A total of 69.5 millimetres (2.7 ins) of rain fell during January, and this was 25% above the long-term average. Measurable rain fell on 15 days, 2 below average, but the 13 wet days (1.0mm/0.04 ins, or more) were 3 days above average. The first fortnight of January only yielded 3.9 millimetres (0.15 inches), but from the 16th to the 24th over 56 millimetres (2.2 ins) was recorded. This included falls of 13 millimetres (0.5 ins) on the 18th, a total of 16.8 millimetres (0.66 ins) on the 22nd, with another 11.6 millimetres falling on the 24th.
Thunderstorms
No thunderstorms were reported.
Hail
Soft hail (snow pellets) fell early in the afternoon on the 5th, with small hail falling as a squally trough passed through at 0040 hours on the 18th. Another soft hail shower occurred at 0017 hours on 20th.
Snow
Light snow fell in the early hours of the 5th. Although it turned to freezing drizzle for a while, a total of 1 centimetre was measured at 0900 hours. Further light snow occurred after mid morning with a ligh snow shower early in the afternoon. Most of the snow had disappeared by evening but thin patches persisted until the 11th. A light flurry of snow occurred before dawn on the 7th, but the only other wintery precipitation that occurred was on the 23rd when rain briefly turned to sleet around 1000 hours.
Wind
Winds were mainly light or gentle east to northeast during the cold spell early in the month, although a moderate northeasterly blew on the 5th. Around the middle of the second week, the winds became southwesterly and for the remainder of the month the direction mostly fluctuated between southeast and southwest. A fresh southwesterly blew on the 11th, and strong southerly winds produced a gust of 44 knots (50 mph) on the 17th. Generally, though the breezes were gentle or moderate, and during the last week occasionally light.
Fog
There was freezing fog very early on the 10th, and on the 14th there was a morning of fog, dense at times.
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