Thursday 9th April
The maximum of 24.1C on Wednesday, logged at 14.26, was a significant 9.8C above my long-term average. It was not the warmest April day that I have recorded since the station was set up in 1984, as 26.2C was recorded in 2011 and 26.5C in 2018. The thermometer would have climbed higher if it were not for thin, high variable cloud that had drifted across during the afternoon and evening, hence the peak mid-afternoon. The considerable warmth only slowly dissipated overnight, at midnight the temperature still read 12.8C. The minimum of 9.2C was recorded at 06.15 early Thursday being 4.9C above average.
The THSW index on Wednesday indicated that although the temperature on a shielded thermometer indicated a temperature of 24.1C, in fact outside it felt more like 27.3C. That is the opposite of wind chill when the strength of solar activity in taken into account during the warmer months.
We were greeted by muted sunshine at the start of Thursday due to thin high cloud still present in the early hours, which also restricted the loss of warmth into the atmosphere, hence the warm night.
Two cold fronts will traverse the country today, that as their name implies will herald a distinct change to our weather with a much cooler air stream following behind, on a westerly air steam. This will have more moisture having traveled over the ocean, and will have originated in the North Atlantic, therefore much cooler than the recent warm air from the Continent, but certainly not Arctic air. Low pressure systems are edging closer to the UK that will mean the breeze picking up after the quiet day on Wednesday, that gave us a maximum movement, couldn’t be called a gust, of just 11mph at 13.28.
The days ahead will become much cooler as a deep depression heads to the north of the country resulting in unsettled weather. Maximum temperatures over the weekend are likely to be a degree or two below average.
Why pollen levels are high this week, and looking ahead
Author: Met Office
A spell of warm, dry and sunny weather has led to rising pollen levels across much of the UK this week.
These conditions are particularly favourable for pollen release and dispersal, meaning many people are likely to notice an increase in hay fever symptoms. While some changes in the weather later in the week may ease pollen levels slightly, high or very high levels are expected to persist for several days, especially in central and southern areas.
This week also marks a key point in the tree pollen season, with birch pollen becoming increasingly dominant, alongside ongoing ash pollen and the early beginnings of oak pollen.
Why pollen levels are high this week
Weather plays a crucial role in both how much pollen is produced and how effectively it spreads. The recent pattern of warm temperatures, sunshine and dry conditions has encouraged trees to release pollen in large quantities. In addition, breezy conditions help pollen grains disperse more widely and remain airborne for longer, increasing exposure.
Warm conditions stimulate pollen development within catkins, while dry air allows pollen to be released more easily. Without rainfall to wash pollen out of the air, levels can steadily build from day to day, which is what many people are experiencing now.
Pollen levels are currently at their highest this week and are expected to remain high, or even very high, through to Friday. Falling temperatures and the increasing risk of showers into the weekend may help reduce levels slightly, but high pollen levels are still possible, part during any dry and bright spells.
Which pollen types are affecting people now
We are currently in the middle of the birch and ash pollen seasons. Birch pollen is now becoming the dominant type and tends to affect a large number of people, often causing more widespread symptoms than ash. Ash pollen levels have already been high, particularly in southern parts of the UK, and the peak is now gradually shifting northwards.
Oak pollen is also just beginning to emerge. While it has not yet reached peak levels, it can still contribute to symptoms, especially for people who are sensitive to multiple pollen types.
Plane pollen may also be present, particularly in urban areas where plane trees are commonly planted. Although it affects fewer people overall, it can still be a trigger for some individuals.