Royston (Iceni) Weather Station

**Daily Weather
Observations - March
2012**

March 2012 Weather Review

(All differences from average quoted in this report relate to the 30 Year period 1981/2010)

The March 2012 weather continued a familiar theme of recent times, the month being warm, dry and sunny.

It was the **mildest** March in Royston since 1997, but even more
significant was the fact that the **mean** daily maximum temperature of
13.6°C (2.9°C **above** average) was the **highest** in March since
records began in 1972.

The **mean** night minimum temperature in the month was 0.4°C **above **
average at 4.0°C. No air frosts occurred in March, the **lowest** night
minimum temperature being 0.5°C on 26^{th}. The **lowest** **grass**
minimum temperature (-3.2°C) of the month was also recorded on this date. It was
the first March with no air frost since 1997. A total of 10 ground frosts
occurred in the month.

The **highest** temperature recorded in March was 21.6°C
on 28^{th}, making this day the equal **warmest **day in March since
at least 1972. The other March day achieving this temperature was 17^{th}
March 1990.

The **mildest night** of the month was 10^{th}
with a minimum temperature of 7.5°C. The **coldest day** in March was 5^{th}
with a maximum temperature of the same value, 7.5°C.

The **mean earth** temperature at 30 cms depth as observed
at 0900 GMT daily was 7.7°C, which is 1.0°C **above** average.

Although the warm spell at the end of March was a newsworthy event it was
overshadowed by the continuing severe drought which has now lasted well over a
year. March started off on a wet note when 14.0 millimetres rainfall was
recorded on 4^{th}, but this turned out to be a false dawn when dry
conditions returned for the rest of the month, and no measurable rainfall at all
was recorded over the period 19^{th} to 31^{st}.

Total rainfall in March was 20.5 millimetres, which is 52% of average. The **
wettest **day of the month was 4^{th} as noted above, whilst the
number of "rain days" (0.2 millimetres or more) was 7, with rainfall exceeding
1.0 millimetre on 3 of these days. March 2011 was a much drier month with only
4.4 millimetres rainfall!

The cumulative total of rainfall for 2012 to the end of March stands at 85.6 millimetres, which is 66% of average.

March was a very sunny month with a sunshine total of 188.0
hours, which is 164% of average. It was the **sunniest** March since 2003
(197.9 hours). The **sunniest** day in March was 28^{th} with 12.2
hours sunshine, but 26^{th}, 27^{th} and 29^{th} also
achieved sunshine totals very close to this figure with sunshine of over 12
hours.

Only 4 days (4^{th}, 12^{th}, 13^{th} and 16^{th})
in March were completely sunless.

The **mean** wind speed in March was 5.0 mph, and the
maximum wind gust recorded was 34 mph on 7^{th}. The **highest**
daily (00/00 GMT) **mean** wind speed was 14.1 mph on 5^{th}, and at
the other end of the scale the **lowes**t daily **mean **wind speed was
1.1 mph on 13^{th}.

Winds with a westerly component accounted for about half the days in the month, with a fairly even distribution of winds across the other sectors, as per the following analysis of daily wind directions at 0900 GMT: NORTH 2 days, NE 2, E 3, SE 5, S 3, W 3, W 8, NW 5 and CALM 0.

The **mean** MSL air pressure was very high at 1027.1 mB,
which is 12.1 mB **above** average. The **highest** and **lowest** air
pressure values recorded in March were 1037.7 mB and 1009.0 mB on 27^{th}
and 7^{th} respectively.

The **mean** relative humidity in the month was 80.9%. The
**highest** daily (00/00 GMT) **mean** relative humidity was 95.2% on 12^{th},
whilst the **lowest** daily **mean** was 52.8% on 28^{th}. The **
absolute** **lowest **relative humidity reading in March was 31% at 1555
GMT on 28^{th}.

The number of days with fog (visibility < 1000 metres @ 0900
GMT) in March was 5 (2^{nd}, 12^{th}, 23^{rd}, 24^{th}
and 25^{th}). On 2 (12^{th} and 23^{rd}) of these days
visibility fell below the 200 metres threshold.

Richard Barker

Richard Barker

Met. Observer, Royston (Iceni) Weather Station

5^{th} April 2012

Return to Daily Weather Observations - March 2012 header page