Weather data recording started in Penallt in March 2011. The charts below show the monthly summaries from January until the end of December 2012 and also compare Penallt's 2012 weather with the 1971-2000 overall average data for Ross-on -Wye, the nearest place for which reliable data exist.
Monthly maximum and minimum temperatures
The chart shows that March was an abnormally warm month, January was a little warmer than usual and that the rest of the year was cooler then average, sometimes considerably so.
- July 25th was the warmest day of the year with a maximum of 27.7°C
- February 8th had the lowest maximum temperature of -0.9°C
- Warmest by night was May 25th with a minimum of 15.3°C
- Coldest by night was February 4th, with a minimum temperature of -7.5°C
- There were 47 days on which the temperature exceeded 20°C and 37 when it was below 0°C
- The mean annual temperature was 9.5°C
2012 started with three drier than usual months with February's 16.8 mm making it unusually dry. Thereafter, every single month was much wetter than the Ross average, June, November and December especially so when monthly rainfalls exceeded 200 mm each time.
The total rainfall for 2012 was 1575.5 mm (62.0 inches), over twice the average Ross total of 706.2 mm (27.8 inches). This is less than the overall 2012 rainfall for Wales of 1716 mm, showing that Penallt was in one of the drier parts of Wales last year!
- Rain was recorded on 239 days in the year
- On average, 4.3 mm rain fell every day during the year
- The wettest day was September 24th when 58.8 mm fell
- 20 mm or more fell on 18 different days