November was a very mild and dry month in Royston, and also a rather sunny one.

The extended ‘Summer’ season this year which began early in April continued through November which turned out to be a very mild month with a mean temperature almost 3°C above normal. It was the mildest November since 1994.

The mean daily maximum temperature in November was 12.7°C, which is 2.8°C above normal. This is the highest mean maximum temperature in November since at least 1972 when records began at this station. The mean night minimum temperature was 2.9°C above normal at 7.9°C.

The highest temperature of the month, 17.0°C on 3^rd, was also noteworthy as this value has been exceeded in November in only 3 years (1984, 2005 and 2010) since 1972. The lowest temperature recorded in the month was 1.6°C on 28^th and this is the highest absolute minimum temperature in November since 1974.

The lowest grass minimum temperature in the month was –0.9°C on 28^th. This was one of only 2 ground frosts in November (compared with 15 in November last year!).

The lowest day maximum temperature was 9.4°C on 23^rd, whilst the highest night minimum temperature was 13.1°C on 3^rd.

The mean earth temperature at 30 cms depth as observed at 0900 GMT daily was 10.3°C. The earth temperature varied from a maximum of 12.2°C on 4^th to a minimum of 8.0°C on 28th.

The rainfall regime in November exhibited the dry conditions of most of the rest of the year and it was yet another dry month. The rainfall total of 30.7 millimetres was only 54% of the 30 Year (1981/2010) average. However, this month contained the wettest day of the year so far when a fall of 22.3 millimetres occurred on 3^rd. In the event this amount was 73% of the month’s total rainfall!

The number of "rain days" (0.2 millimetres or more) in November was 10, with rainfall exceeding 1.0 millimetre on 5 of these days. It was the driest November since 1999.

The 2011 cumulative total of rainfall for January to November was 349.5 millimetres, which is only 63% of the 1981/2010 average. Looking slightly ahead, if December rainfall is average or below it will be the driest year in Royston since 1921.

November sunshine has increased markedly in the last few years but sunshine this November struggled to keep up with this trend, but sunnier conditions in the second half of the month resulted in sunshine just reaching the average of the last 10 years by the end of the month. However, when compared with the longer term 30 Year average for 1971/2000 the November sunshine total was 26% above this figure and thus qualifies as a rather sunny month (but sunniest since 2009 only).

The sunniest day of the month was 19^th with 7.5 hours sunshine. After only 2 days being completely sunless between 16^th March and 31^st October no less than 6 such days occurred in November.

The mean wind speed in November was 5.9 mph and the maximum wind gust recorded was 40 mph on both 27^th and 29^th. The windiest day (00/00 GMT) of the month was 29^th with a mean wind speed of 13.7 mph. At the other end of the scale the calmest day of the month was 8^th with a mean wind speed of 1.3 mph.

Winds with a southerly component were in the ascendancy in November as per the following analysis of wind directions as observed at 0900 GMT daily: NORTH 1 day, NE 2, E 5, SE 6, S 10, SW 3, W 3, NW 0 and CALM 0.

The mean MSL air pressure in the month was 1016.5 mB, which is 2.8 mB above the 1981/2010 average. The highest and lowest air pressure values in the month were 1029.7 mB and 989.4 mB on 12^th and 4^th respectively.

The mean relative humidity in November was 90.2%. The highest daily (00/00 GMT) mean relative humidity was 97.0% on 22^nd, whilst the lowest daily mean was 74.9% on 27^th. The absolute lowest relative humidity reading in November was 56% at 1345 GMT on 27^th.

Fog (visibility < 1000 metres @ 0900 GMT) was observed on 5 days (5^th, 7^th, 16^th, 21^st and 22^nd) in November.

AUTUMN (September/November) 2011: It was the equal (with 2006) warmest Autumn on record (1972). It was also the driest Autumn since 1978. The mean daily maximum temperature in Autumn was 17.2°C, which is 2.6°C above the 30 Year (1981/2010) average. The mean night minimum temperature was 2.1°C above average at 10.1°C. Total rainfall in Autumn was 67.9 millimetres (39% of the 1981/2010 average). Sunshine recorded amounted to 457.8 hours, which is 141% of the 1971/2000 average.

Met. Observer, Royston (Iceni) Weather Station

7^th December 2011