To know whether a month was unusual, you first need to know what a normal month looks like here. Working that out properly takes about thirty years of records. This station has not been running anywhere near that long. So the long records on this page come from another weather station nearby, and this page compares our readings against them.
The difference between the two baselines is not a trend. We have two averages: one for 1971 to 2000, and one for 2005 to 2024. Two numbers can show that something changed. They cannot show how fast it changed, or whether it is still changing. The chart at the top does draw a trend line, but that line is worked out from twenty separate yearly averages, not from these two numbers. If the maths says the slope could just as easily be flat, we do not draw the line at all.
A difference between the two baselines is not always the climate changing. The old averages stop in 2000. The newer records start in 2004. There is no period when both were being measured, so we cannot check one against the other. Rainfall shows the problem. Every single year since 2005 has been wetter than the old thirty-year average, and not one came close to it. Real weather is not that consistent. It is far more likely that the rain gauge was moved, or something changed around it. So we leave the rainfall comparison out, and say why.
A month with gaps in it is not a fair average. If this station missed a fortnight of a month, the average for that month is really only an average of the days it caught. We do not work out how unusual a month like that was. We print how many days were actually recorded instead.
There are two ways to work out an average temperature for a month, and they do not agree. The old way takes the highest and lowest reading of each day, adds them, and halves the result. Every official climate average in the world is worked out this way, because for most of history somebody read a thermometer twice a day and that was all anyone had. This station takes a reading every minute, so it can work out a true average across the whole day. The true average comes out a little lower. If we compared our true average against an official one, every month would look colder than it really was, by about the amount real weather would shift it. So we use the old method on both sides and compare like with like.