There may well be a warm spell coming later this week, but I’m afraid that even with these high temperatures, April 2018 won’t be a patch on the exceptionally warm April of 2011 (fig 1), which in fact was the warmest since the data series began in 1659 (fig 2) with an anomaly of +3.93°C. It didn’t just sneak past the previous warmest April it smashed past it (fig 2) by over 0.6°C (2007), which in itself was over 0.5°C warmer than the previous warmest April. Is it just me, or do we all have short memories of memorable warm spells?
Here’s April 2011 in a little more detail from the daily series of the CET (fig 3).
To give you an idea of just how warm it was, here are the hourly temperatures and running 24 hour mean from Heathrow airport courtesy of OGIMET (fig 4).