From Tallbloke’s Talkshop

By Ray Sanders 

In my recent review of Barkston Heath Airfield I noted that despite appearing in “Daily Extremes” none of the site’s data was archived or visible in any way to the general public directly from the Met Office. In that review I referred to my previous review of Gosport where exactly the same situation prevailed. Yet now Gosport is reporting the daily extreme highest national temperature. How sure can the public actually be that such figures are accurate when there is no public access to the site nor public record. This warranted further investigation.

Worrying issues at Gosport include the military nature of the site with the very largest of helicopters – Chinnok – based at the site and almost certainly passing overhead of the temperature sensors. Exhaust heat and rotor-wash are well known phenomena with a significant likelihood of adversely affecting readings accuracy. Clicking on the hyperlink for Gosport offers this below for Thorney Island plus the suggestion of looking for other nearby places.

Firstly, it must be remembered that a modern Platinum Resistance Thermometer (PRT) is very rapidly responsive to temperature changes. Former Liquid in Glass Thermometers (LIGT) were much slower to respond and were very much less likely to respond to brief transient heat bursts specifically aviation effects.

Met Office PRT readings protocol is to take readings every 15 seconds, add 4 consecutive readings together and divide by 4 to provide 1,440 daily averaged readings i.e. one every minute. The maximum and minimum of each day is then added together and divided by 2 to provide a daily meteorological “mean”. This “extremes only” system is therefore highly responsive to any tiny change in these extremes.

The Met Office has reported a national daily high of 18.5°C for 16th October 2025 at Gosport. I shall investigate via those “other nearby locations” to ascertain just how sure the public actually can be this is a real natural temperature reading or alternatively some unnatural artificial event. Weatherobs.com offers site readings for Gosport on the hour. The maximum reported figure was only 17.1°C at 12:00 GMT. Readings either side were 15.75°C at 11:00 and 16.15°C at 14:00. Mysteriously (as is so often the case) the potentially peak time of 13:00 reading is missing.

The situation here is that the maximum reading of 18.5°C is very much higher than those available readings but could well have occurred within that two hour gap period from midday onwards. How does the temperature profile for Gosport compare with neighbouring sites that are visible from Met Office sites? Thorney Island is under 10 miles distant to the east and demonstrably acts as the proxy for Gosport. The Met Office WOW graph below indicates time in BST so 1 hour adjustments are required.

The Met Office WOW 13:00 BST reading at Thorney Island peaked at just 16°C and equates to the 12:00 GMT Gosport weatherobs reading of 17.1°C. Thorney Island readings then fell away never reaching within 2.5°C of Gosport’s claimed peak.

Moving west of Gosport produces the similarly non archived Met Office Southampton Oceanography centre, yet again mysteriously not supplying the 13:00 reading but also not registering within 2°C of that 18.5°C maximum.

Moving onto private weather stations reporting to the Met Office WOW site there is one at Lee-on-the-Solent under 3 miles from the Gosport site. Despite every hour readings, again none came within 2°C of Gosport.

Moving in even closer to Southsea at less than 1.5 miles away, again no readings come close to matching Gosport’s claimed peak.

At this point none of the multiple official Met Office nor reliable private sites in the vicinity (shown below with Gosport itself as the blue dot) either followed the unusually spiky temperature profile displayed by the Gosport readings or got particularly close to the “extreme” national high reading for the day

This is not positive disproof of the Met Office reading, however

1. The Met Office does not directly show the previous days readings for Gosport only offering Thorney Island in lieu.
2. None of the surrounding sites appear to have come within 2°C of the reported maximum.
3. None of Gosport’s readings are ever archived for public viewing.
4. The site is in a restricted area unavailable for public scrutiny

Below is a reminder of the type of activity at Gosport Fleetlands.

Are Met Office temperature readings always trustworthy? Who knows.