Royston (Iceni) Weather Station
Daily Weather Observations - April 2011
(All Times GMT)
| Date | Max. Temp. (°C) 09/09h | Min. Temp. (°C) 09/09h | Grass Min. Temp. (°C) 21/09h | Earth (30cms) Temp. (°C) 09h | Sun (Hours) 00/00h | R'fall (MM) 09/09h | Wind Dir'n 09h | Mean Wind Speed (MPH) 00/00h | Max. Gust Speed (MPH) 00/00h | Cloud Cover (Oktas) 09h | Mean MSL Air Pressure (mB) 00/00h | Mean Rel. Humd. (%) 00/00h | Mean Temp. (°C) 00/00h | Fog (vis. <1000m @ 09h) | Fog (vis. <200m @ 09h) | Snow or Rain and Snow 00/00h | Snow Lying @ 09h (>50% cover) | Hail 00/00h | Thunder 00/00h | Date |
| 1 | 17.0 | 11.0 | 8.6 | 9.9 | 3.9 | 0.0 | SW | 11.6 | 32 | 8 | 1015.7 | 83.1 | 13.1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 2 | 18.1 | 10.4 | 8.3 | 10.3 | 2.6 | 0.0 | S | 9.3 | 28 | 7 | 1009.4 | 76.0 | 13.7 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| 3 | 14.9 | 6.1 | 3.1 | 10.5 | 4.4 | 2.5 | SW | 7.0 | 24 | 4 | 1013.2 | 76.3 | 10.1 | 0 | 0 | 0 | 0 | 0 | 0 | 3 |
| 4 | 13.3 | 4.5 | 2.6 | 10.0 | 5.5 | 1.2 | SW | 10.1 | 29 | 2 | 1019.2 | 77.3 | 9.1 | 0 | 0 | 0 | 0 | 0 | 0 | 4 |
| 5 | 15.8 | 8.4 | 7.6 | 10.0 | 0.1 | TR | SW | 13.5 | 40 | 8 | 1019.1 | 86.9 | 11.2 | 0 | 0 | 0 | 0 | 0 | 0 | 5 |
| 6 | 23.0 | 11.8 | 10.9 | 10.5 | 10.8 | 0.0 | SW | 8.4 | 25 | 4 | 1023.7 | 66.7 | 16.5 | 0 | 0 | 0 | 0 | 0 | 0 | 6 |
| 7 | 19.9 | 9.4 | 6.2 | 11.4 | 9.9 | 0.0 | NW | 6.9 | 19 | 1 | 1026.6 | 72.1 | 13.8 | 0 | 0 | 0 | 0 | 0 | 0 | 7 |
| 8 | 21.5 | 6.2 | 2.6 | 11.4 | 12.8 | 0.0 | NW | 3.6 | 14 | 0 | 1026.9 | 69.1 | 13.0 | 0 | 0 | 0 | 0 | 0 | 0 | 8 |
| 9 | 19.7 | 5.8 | 1.6 | 11.7 | 12.6 | 0.0 | NE | 3.4 | 16 | 0 | 1025.9 | 66.5 | 11.9 | 0 | 0 | 0 | 0 | 0 | 0 | 9 |
| 10 | 19.7 | 2.5 | -1.0 | 12.0 | 12.6 | 0.0 | NE | 1.9 | 13 | 5 | 1024.3 | 63.6 | 10.8 | 0 | 0 | 0 | 0 | 0 | 0 | 10 |
| 11 | 21.3 | 7.3 | 2.3 | 11.5 | 8.6 | 1.1 | W | 7.4 | 33 | 4 | 1021.5 | 68.5 | 12.3 | 0 | 0 | 0 | 0 | 0 | 0 | 11 |
| 12 | 15.0 | 3.7 | 1.5 | 11.6 | 10.0 | TR | NW | 7.9 | 26 | 2 | 1028.3 | 65.6 | 8.5 | 0 | 0 | 0 | 0 | 0 | 0 | 12 |
| 13 | 11.8 | 4.6 | -1.0 | 11.0 | 0.1 | TR | S | 5.0 | 18 | 8 | 1022.1 | 66.7 | 8.1 | 0 | 0 | 0 | 0 | 0 | 0 | 13 |
| 14 | 14.0 | 7.0 | 6.1 | 10.7 | 0.1 | 0.0 | S | 4.5 | 17 | 8 | 1018.1 | 75.4 | 10.3 | 0 | 0 | 0 | 0 | 0 | 0 | 14 |
| 15 | 16.1 | 9.2 | 7.9 | 11.0 | 0.9 | 0.0 | S | 4.0 | 14 | 7 | 1019.7 | 71.9 | 12.2 | 0 | 0 | 0 | 0 | 0 | 0 | 15 |
| 16 | 17.5 | 9.8 | 7.4 | 11.5 | 5.1 | 0.0 | W | 3.5 | 13 | 2 | 1021.9 | 74.8 | 12.7 | 0 | 0 | 0 | 0 | 0 | 0 | 16 |
| 17 | 19.9 | 7.9 | 3.7 | 11.5 | 4.9 | 0.0 | E | 1.9 | 11 | 3 | 1024.3 | 73.8 | 12.7 | 0 | 0 | 0 | 0 | 0 | 0 | 17 |
| 18 | 18.2 | 4.0 | 0.2 | 11.9 | 7.7 | 0.0 | N | 1.7 | 15 | 8 | 1018.5 | 69.5 | 10.9 | 0 | 0 | 0 | 0 | 0 | 0 | 18 |
| 19 | 23.7 | 6.1 | 1.7 | 11.8 | 11.9 | 0.0 | W | 1.7 | 16 | 1 | 1012.9 | 72.6 | 13.6 | 0 | 0 | 0 | 0 | 0 | 0 | 19 |
| 20 | 24.8 | 6.0 | 2.5 | 12.5 | 10.9 | 0.0 | N | 1.9 | 10 | 0 | 1014.7 | 71.0 | 14.3 | 0 | 0 | 0 | 0 | 0 | 0 | 20 |
| 21 | 24.7 | 6.7 | 2.6 | 13.0 | 11.5 | 0.0 | NE | 1.9 | 15 | 4 | 1013.0 | 65.4 | 14.8 | 0 | 0 | 0 | 0 | 0 | 0 | 21 |
| 22 | 25.5 | 9.4 | 4.2 | 13.2 | 13.2 | 0.0 | E | 2.8 | 15 | 0 | 1008.4 | 57.5 | 17.5 | 0 | 0 | 0 | 0 | 0 | 0 | 22 |
| 23 | 27.1 | 10.0 | 5.5 | 13.8 | 13.0 | 0.0 | E | 1.9 | 16 | 0 | 1011.6 | 56.8 | 18.7 | 0 | 0 | 0 | 0 | 0 | 0 | 23 |
| 24 | 20.3 | 9.4 | 5.5 | 14.5 | 10.1 | 0.0 | N | 3.5 | 15 | 3 | 1018.8 | 80.3 | 14.1 | 0 | 0 | 0 | 0 | 0 | 0 | 24 |
| 25 | 21.6 | 5.7 | 2.0 | 14.3 | 13.4 | 0.0 | N | 4.8 | 24 | 0 | 1023.9 | 72.1 | 12.3 | 0 | 0 | 0 | 0 | 0 | 0 | 25 |
| 26 | 15.7 | 8.4 | 6.4 | 14.4 | 2.5 | 0.0 | N | 5.3 | 18 | 8 | 1025.8 | 81.3 | 10.5 | 0 | 0 | 0 | 0 | 0 | 0 | 26 |
| 27 | 17.2 | 6.3 | 2.6 | 13.7 | 10.7 | 0.0 | NE | 5.1 | 22 | 7 | 1025.7 | 73.8 | 10.0 | 0 | 0 | 0 | 0 | 0 | 0 | 27 |
| 28 | 15.4 | 2.9 | -2.0 | 13.6 | 1.3 | 0.0 | N | 5.7 | 24 | 7 | 1019.5 | 84.2 | 9.5 | 0 | 0 | 0 | 0 | 0 | 0 | 28 |
| 29 | 20.5 | 9.2 | 9.0 | 13.5 | 4.4 | 0.0 | NE | 4.3 | 19 | 8 | 1012.8 | 80.8 | 13.0 | 0 | 0 | 0 | 0 | 0 | 0 | 29 |
| 30 | 21.4 | 7.9 | 3.9 | 13.8 | 13.5 | 0.0 | NE | 5.3 | 23 | 0 | 1010.3 | 72.3 | 13.5 | 0 | 0 | 0 | 0 | 0 | 0 | 30 |
| Total/Mean | 19.2 | 7.3 | 4.1 | 12.0 | 228.7 | 4.8 | X | 5.2 | X | 4.0 | 1019.2 | 72.4 | 12.4 | 0 | 0 | 0 | 0 | 0 | 0 | Total/Mean |
| *Diff./% | +5.5 | +2.5 | 157% | 11% | *Diff./% | |||||||||||||||
| Date | Max. Temp. (°C) 09/09h | Min. Temp. (°C) 09/09h | Grass Min. Temp. (°C) 21/09h | Earth (30cms) Temp. (°C) 09h | Sun (Hours) 00/00h | R'fall (MM) 09/09h | Wind Dir'n 09h | Mean Wind Speed (MPH) 00/00h | Max. Gust Speed (MPH) 00/00h | Cloud Cover (Oktas) 09h | Mean MSL Air Pressure (mB) 00/00h | Mean Rel. Humd. (%) 00/00h | Mean Temp. (°C) 00/00h | Fog (vis. <1000m @ 09h) | Fog (vis. <200m @ 09h) | Snow or Rain and Snow 00/00h | Snow Lying @ 09h (>50% cover) | Hail 00/00h | Thunder 00/00h | Date |
Differences from average:
Differences from average shown in red. Reference periods used are as follows: Temperature 30 Years 1976/2005; rainfall 30 Years 1971/2000; sunshine 30 Years 1971/2000.
(*The differences from average quoted during the course of the month relate to the cumulative daily averages up to the date of the last observation, not the averages for the month as a whole)
Additional Data:
Rainfall Duration N/A
Air Frost Duration NIL hours
Graphs and Charts:
Click on the following links to view this month's graphs and charts.....
1. Daily Maximum, Minimum & Grass Minimum Temperatures
2. Daily Maximum & Minimum Temperatures (with 30 Year Comparative Means)
3. Daily Earth (30 cms Depth) Temperature @ 0900 GMT 4. Daily Rainfall 5. Daily Sunshine
6. Daily Maximum Gust & Mean Wind Speed 7. Daily Wind Direction @ 0900 GMT
8. Daily Mean MSL Air Pressure 9. Daily Mean Relative Humidity 10. Thermograph
11. Barograph 12. Hygrograph 13. Anemograph 14. Wind Direction
15. Rainfall Intensity & Duration
April 2011 Weather Review:
......and click on the link below for a text report of the April 2011 weather in Royston
April (since 1973) at Royston (Iceni) Weather Station:
Mean daily maximum temperature (30 years 1981/2010) 13.7°C
Mean daily minimum temperature (30 years 1981/2010) 4.8°C
Highest temperature 25.5°C (16th April 2003); lowest temperature -4.1°C (11th April 1978)
Lowest grass minimum temperature -9.4°C (4th April 1996)
Warmest April 2007 (Mean temperature 12.3°C); coldest April 1978 (Mean temperature 6.2°C)
Average April rainfall (30 years 1971/2000) 43.8 mm
Wettest April 1998 (Rainfall 120.7 mm); driest April 2007 (Rainfall 1.6 mm)
Wettest Day 9th April 1998 (Rainfall 32.0 mm);
Highest number of "rain days" (0.2 mm or more) 26 (1998); lowest number of "rain days" 3 (2007)
Highest number of days with thunder 7 (1998)
Highest number of air frosts 8 (1975)
Highest number of ground frosts 15 (1974, 1984)
Highest number of days with snow falling 5 (1975, 1986)
Highest number of days with snow lying (ground with more than 50% snow cover @ 0900 GMT) 2 (1978, 1983)
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| This is the Cross in the centre of Royston, at the intersection of the Roman road Ermine Street and the ancient Icknield Way, this view being from the south side at 1549 GMT on 8th April 2011. In the shadows in the foreground is the famous Royse Stone. A hole in the top of the Royse Stone originally housed a wayside cross to mark this intersection. Today this point has been chosen to represent the beginning and end of the Hertfordshire Way, a 310 km footpath around the county. On the opposite side of the road is the entrance to the equally famous Royston Cave, a bell shaped chamber hewn out of the chalk strata on which the town of Royston is built. This has been a glorious Spring day as indicated by the late afternoon sunshine in evidence. A total of 12.8 hours sunshine had been accumulated by the end of the day and a maximum temperature of 21.5°C achieved, a value which is exactly 10°C above the 30 Year average for this day of the month! | The annual St. George's Day festival at Wrest Park (27 km SSW of Royston) was held over 3 days of the 2011 Easter Weekend (23rd to 25th April). The event enjoyed virtually continuous sunshine throughout and attracted large crowds. This picture shows a serious situation developing after a jousting tournament between two rival knights. The adjudication of the event by the Knight Marshall has proved controversial and he has just been struck by one of the knights in contravention of the keeping of the King's Peace. This has inflamed tensions between the rival supporters, one group of which in this picture are arming themselves ready for a fight with the opposition. General mayhem is about to commence! All good fun! As regards the weather on this day a maximum temperature of 27.1°C occurred at Royston making it the warmest April day since at least 1972 when records began. Also, at Royston sunshine of 13.0 hours was recorded. | This is the reserve wind vane and anemometer in use at Royston (Iceni) Weather Station, as viewed from below on 25th April 2011 (note the clear sky as in the previous two photographs in this exceptionally sunny (and warm and dry) April. This instrument is mounted on its own dedicated mast and is connected by a cable (out of view on other side of mast) to a wireless data transmitter at the foot of the mast. From here the data is transmitted wirelessly to an indoors console from which it is downloaded to a PC and exported to spreadsheets. The datalogger can be set to log the data at any chosen interval and at this station a 5 minute period is used as a compromise between maximising the amount of data recorded and optimal use of the memory available. Considering the buffeting these seemingly fragile looking instruments receive from the wind they are surprisingly robust and will give several years service without any attention, a solar panel providing electrical power for the transmitter. |
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(This page last updated 10th May 2011 2020 GMT)