With the UK under unprecedented lockdown due to COVID19, the sunniest April on record was followed by the sunniest May on record. I can hear the conspiracy theorists now …
The meteorological year starts in December which is why December appears as the 1st data point in the charts below. More information on the layout of the charts can be found in this post. Points lying between the upper and lower deciles are shown as open black circles, points lying between the deciles and minimum/maximum are shown as solid black circles and any month with a new record is shown as solid black squares. All data is supplied by the Met Office and can be found here.
As I explained in October 2018, the addition of a Temperature Range chart (B) means I update 7 charts every month so I rotate which 6 appear in the deck above and plot the 7th as a separate chart here. Since it is no longer Winter, Frost (chart G) is shown here since that is of least interest in these months.
How abnormal was May 2020?
Chart H displays my UK Weather Abnormality Index (Scroll down my May 2019 post for details). The closer to zero this index is, the less abnormal and thus more “average” a month is. The higher it is, the more abnormal the month is. When the index is over 100%, we can describe the month as unusual in some way.
The abnormality index was 138% in May 2020 which is the highest on record for May. Like April, this is due to a combination of record sunshine, 4th highest temperature range and 8th lowest rainfall on record. In other words it was a beautiful and very unusual May.
May marks the end of the meteorological spring. I do not track regional statistics every month but I do track temperature by season for each region so I can update the regional temperature chart here. This shows the Z-Score for each region for the 2019 autumn. A Z-Score is simply the regional temperature minus the long term average for that region divided by the long term standard deviation for that region. Doing this, gets around the issue that each region is different on average whereas z-scores all have the same scale, namely number of standard deviations from the mean.
For the UK as a whole, the 2020 spring was well above average in temperature in all regions with the South West the warmest region. At the other end, Northern Scotland was also above average but less remarkably so.
PS: If you bookmark this link, it will be refreshed with the latest month’s data. I usually post the update in the first week of each month.
Click the relevant month to see my other weather trackers. Alternatively click the Weather Tracker hash tag below this post to see a list of all such posts.
- Click here for the latest month.
- 2020 – January, February, March, April, May, June, July, August, September, October, November, December
- 2019 – January, February, March, April, May, June, July, August, September, October, November, December
- 2018 – January, February, March, April, May, June, July, August, September, October, November, December
- 2017 – January, February, March, April, May, June, July, August, September, October, November, December
For analysis of trends by seasons, please click on the relevant season from this list or the Weather Trends hashtag below this post.