Yesterday gave us 14.87 hours of strong sunshine, the highest total since 30th June 2015. The southerly breezes (high 19 mph) modified the maximum temperature to 16.7C, average for early May. Clear skies overnight produced another cool morning with a minimum of 1.3C but the strong sunshine from dawn meant that the thermometer had risen to 9.2C at 08.00 with low humidity of 73% at this time. UV levels this month are nudging into the ‘High’ category.
The brisk westerly winds yesterday kept the temperature down to a maximum of 14.6C but with the high pressure now nearby we enjoyed 8.91 hours of strong sunshine. Overnight, as the little cloud cleared, the thermometer dropped to a minimum of 0.2C by 05.15 producing a ground frost that disappeared quickly in the rising sun. By 08.00 the thermometer reading was 7.7C and already 1.8 hours of strong sunshine had been recorded.
Yesterday the southerly air boosted the temperature to a maximum of 16.1C (average for early May) just after noon with broken sunshine in the morning. The advancing cold front brought thick cloud in the afternoon with modest rain totalling 2.3mm.
As the cold front passed over around 17.00, the wind veered into a westerly direction and the sun came out again taking the total hours of strong sunshine yesterday to 2.28 hours.
This morning dawned with strong sunshine and a little high cloud with a temperature of 7.5C at 08.00.
This was a Spring month that did not spring!
We suffered seven nights with an air frost, two above average, the lowest being -3.2C on the 28th and hail in rain showers on two days. There was snow in the rain showers on the 9th and sleet on the 16th plus fog banks in the early morning of the 13th. The coldest April night on record occurred in 1990 when the thermometer plunged to -6.9C, which was very cold for an April night.
April was a cold month with a mean temperature 1.1C below the 32-year average, the coldest since 2013. I have only recorded five colder Aprils in the past 34 years. There was a slightly warmer period of three days around the middle of the month with a maximum of 16.5C, which is only 2C above the mean.
The rainfall total was 49.6mm, which is 10mm below the 32-year average making it the first drier than average month this year. There were fifteen wet days, the average is ten, with the 10th providing the highest daily total with 9.6mm.
Due to the reduced rainfall and many days with drying winds from an easterly quarter the evaporation from ground and plant life totalled 63.5mm, giving a deficit over precipitation of 14mm.
Solar power for the month was close to the average but much less than the exceptional April of last year. There was a total of 114 hours of strong sunshine this year whereas last year we enjoyed 186 hours. This instrument was only installed in 2013 so I have limited historical data.
It is not surprising that the ground temperature at a depth of 5cm is the lowest for several years with an average of 6C, being 2C below the average over the last few years.
After a dismal month, we can look forward to a significant change in the scenery. This quotation from L.H.Bailey sums up the current situation, as with warmer air forecast we will see a profusion of leaves and blossom over the next couple of weeks. “Yesterday the twig was bare; today the glint of green is there; tomorrow will be leaflets spare; I know no thing so wondrous fair, no miracle so strangely rare. I wonder what will next be there!”
The last day of April brought 6.0 hours of strong sunshine but with clearing skies overnight another air frost occurred for a couple of hours before dawn with a minimum of -0.7C.
The humidity at 08.00 today was very low at 71% with bright sunshine that soon was dimmed with high level cloud.