Monthly Weather Review - Pitsford Hall

Headline: Changeable, but drier than normal with a wet unsettled spell around mid-month.

May began with a deep low north-west of Ireland drawing up a southerly airflow across much of the UK, this southerly flow turning more west or north-westerly over the next few days. It was reasonably warm to begin with across Northampton with some good spells of sunshine recorded between the 1st and 3rd, although rain bands did track eastwards but introducing little more than trace amounts of rain. It was also quite windy at times; gusts exceeding 30mph on the 5th and again on the 8th.

An anticyclone became established to the north of Scotland on the 10th and this resulted in a spell of dry settled weather across Northamptonshire, although the steepening pressure gradient towards the south of this system saw some strong easterly winds in this area and these served to prevent temperatures rising too noticeably during the daytime and some night-times became rather chilly.

Low pressure tracked north-westwards across the UK on the 15th after which conditions remained cyclonic with a depression fairly stationary near Ireland. The weather across Northampton was dominated by showers, some rather heavy at first. Although nearly 7 hours of sunshine was recorded on the 16th, most days remained rather cloudy and breezy too at times.

Unsettled conditions continued until the 21st after which a ridge of high pressure extended across the UK. The 23rd and 24th as a result were warm sunny days, both recording in excess of 11 hours of sunshine in a just a light breeze. Temperatures for the first time in May topped 20C on the 23rd, climbing steadily towards 23C and higher on the 25th. However, an eastward moving cold front introduced rain on the 25th and winds picked up too gusting to 40mph on the 26th but remaining strong during the days on either side.

From the 28th onwards high pressure would control the UK weather, moving north-eastwards across the country and then staying fairly stationary over southern Scandinavia. The weather across the county settled down and became very warm with highs reaching 24C on the 29th with just a light breeze from the north or north-east. The 28th was a particularly humid day; cloudy with little sunshine – although the days that followed were much fresher. The month ended with two fine days of almost unbroken sunshine.

Statistically, May was much warmer than normal although not as warm as May last year which saw an average temperature of 13.7, a good 2C above average. Nevertheless, the month was very dry receiving just over half the expected amount of rainfall making this the driest May in the county since 1998 when just 12.0mm was recorded. By contrast sunshine totals came in at around average.


Air Temperatures    
The Highest Maximum: 24.0 C on 29th
The Lowest Maximum: 13.0 C on 17th
The Highest Minimum: 11.2 C on 29th
The Lowest Minimum: 3.6 C on 4th
The Mean Maximum: 17.5 C  
The Mean Minimum: 7.9 C  
The Overall Mean: 12.7 C  
Difference from the Monthly Mean: +1.1 C  
    
Black Bulb    
Maximum (at 0900): 31.2 C on 30th
Mean (at 0900): 19.6 C  
    
Relative Humidity:    
Highest Relative Humidity (at 0900): 97.7 % on 15th
Lowest Relative Humidity (at 0900): 50.2 % on 12th
Mean Relative Humidity (at 0900): 73.6 %  
    
Dew Point:    
The Highest Dew Point (0900): 15.9 C on 28th
The Lowest Dew Point (at 0900): 2.0 C on 8th
The Mean Dew Point (at 0900): 8.3 C  
    
Rainfall:    
Total: 26.8 mm  
Percentage of the Monthly Mean: 54.3 %  
Duration: 18.2 hrs  
Highest 24 hour fall (0900 to 0900): 9.1 mm on 14th
Rain Days (>/=0.2mm): 11   
Wet Days (>/=1.0mm): 6   
    
Sunshine:    
Total Duration of Bright Sunshine: 194.3 hrs  
Sunniest day: 14.0 hrs on 30th
No. of days without sunshine: 2   
Percentage of the Monthly Mean: 105.1 %  
Cloud cover (mean at 0900): 4.9 oktas 61.3 %
    
Pressure (reduced to sea level):    
The Highest Pressure (at 0900): 1032.8 mb on 29th
The Lowest Pressure (at 0900): 1000.7 mb on 15th
Mean Pressure (at 0900): 1018.4 mb  
    
Winds    
Run of wind (mean over 24 hrs): 122.8 miles  
Mean daily wind speed: 6.7 mph  
Run of wind (cumulative): 3807.3 miles  
Highest Maximum Gust: 40 mph on 26th
No. of gusts of 50mph or more: 0   
Highest wind strength (at 0900): 26.5 mph on 26th
Mean wind strength (at 0900): 11.2 mph  
    
Winds from the Following Directions:    

N1 NE 5 E 4 SE 2 S 8 SW 3 W 4 NW 3 Calm 1
    
Concrete     
Lowest Concrete Minimum: 3.6 C on 4th
Mean Concrete Minimum: 7.9 C  
    
Evaporation    
Piche 113.5 ml  
Pan 91.34 mm  
    
Days with:    
Thunder: 0   
Hail <5mm: 0   
Hail >/=5mm: 0   
Snow or snow & rain: 0   
Snow lying: 0   
Fog: 0   
Air Frost: 0   
Gales: 0   

All data © Pitsford Hall weather station.

The weather station publishes a full Monthly Weather Report (ISSN 1741-4733) which is distributed to libraries across Northamptonshire. This report comprises a full UK weather diary, reports of extreme weather events across the county, statistics from Pitsford Hall's affiliated stations across the county as well as news from the weather station itself. Individuals may download this report for £2 or take out an annual subscription for the paper-based report for £25. Click here for further details.