April 2021

Glorious gorse in flower along the coast path of Devon on a sunny April afternoon

A really remarkable month in every way. The coldest, driest and sunniest April in my record (2005). The 2nd highest number of air frosts, only being beaten by December 2010. Joint highest number of ground frosts. Normally, cold Aprils are wet and dull, that went out of the window with this month. The warmest day occurred on the 1st, another feat in itself given the how strong the sunshine gets through the month. Lowest mean minimum temperature since December 2010 - in April!.

Summary for April 2021
Mean Max: 14.2ºC (+1.0ºC)
Mean Min: 1.3ºC (-3.7ºC)
Mean: 7.8ºC (-1.3ºC)
High Max: 18.2ºC 1st
Low Max: 9.8ºC 7th
High Min: 9.5ºC 24th
Low Min: -2.4ºC 17th
Mean Grass Min: -1.5ºC  
Grass Min: -6.1ºC 6th
Days  >15°C 11 Days  
Days >10°C 29 Days  
Nights  >5°C 6 Days  
Nights  >0°C 13 Days  
Rain Total (gauge): 11.8 mm (19%)
Rain Total (tipping bucket): 11.4 mm (19%)
Rain Days >0.2 mm: 3 Days  
Rain Days >1.0 mm: 2 Days  
Max 24 hrs: 9.6 mm 28th
Days without any rain: 27  
Air Frost: 17 Days  
Grass Frost: 22 Days  
Snow Falling: 0 Days  
Snow (50%) @ 9am: 0 Days  
Ice Days: 0 Days  
Thunder Heard: 0 Days  
Hail <5 mm: 0 Days  
Hail >5 mm: 0 Days  
Fog @ 9am: 0 Days  
Total Monthly Sunshine: 268.4 Hours (133%)
Most Sunshine in a Day: 13.9 Hours 26th
Average Daily Sunshine: 8.9 Hours  
Sunless Days: 0 Days  
Cloudless Days: 0 Days  
Total Possible Sunshine: 415.6 Hours  
Percentage of Total Sun: 65%  
Average Sunny Interval: 23.4 mins
Maximum UV Index: 6.3 25th
Mean Soil Temp @ 10 cm: 9.0ºC  
Min Soil Temp @ 10 cm: 7.6ºC 7th
Max Soil Temp @ 10 cm: 10.2ºC 28th
Mean Soil Temp @ 30 cm: 9.1ºC  
Min Soil Temp @ 30 cm: 8.3ºC 9th
Max Soil Temp @ 30 cm: 10.1ºC 27th
Mean Soil Temp @ 100 cm: 9.4ºC  
Min Soil Temp @ 100 cm: 8.9ºC 17th
Max Soil Temp @ 100 cm: 10.0ºC 28th
Ave 10 Min Wind >39 mph: 0.00 Days  
N: 9.31 Days 30%
NE: 3.45 Days 11%
E: 2.51 Days 8%
SE: 2.10 Days 7%
S: 2.75 Days 9%
SW: 1.76 Days 6%
W: 0.39 Days 1%
NW: 2.84 Days 9%
Calm: 4.90 Days 16%
Wind Chill Low: -4.1ºC 6th
Mean Wind: 3.1 mph  
Max Gust: 26 mph 5th
Mean Cloud Cover: 35%  
Mean RH @ 9am: 83%  
Rain >0.1mm/hour: 3.1 Hours  
Frost Duration: 81.2 Hours  
Air Frost in a Day: 9.2 Hours 6th
Mean Sea Temperature: 10.2ºC (-0.2ºC)
Normal for Month: 10.4ºC  
Max Sea Temperature: 12.2ºC 20th
Min Sea Temperature: 8.8ºC 8th
Mean Pressure @ 9am: 1023.6 hPa  
Mean Pressure: 1022.8 hPa  
Max Pressure: 1034.2 hPa 15th
Min Pressure: 1004.3 hPa 28th
Max Change in 24 hours: 11.5 hPa 11th
Radiation Daily Mean: 18.45 MJ/m²  
Max Daily Value: 26.66 MJ/m² 26th
Min Daily Value: 10.52 MJ/m² 8th
Number of Days with Data: 30 Days  
1-Hour Maximum: 778 W/m² 27th
Starting Time of the Hour:   13:00
Max Dewpoint: 12.5ºC 1st
Min Dewpoint: -4.5ºC 6th
Mean Dewpoint: 3.0ºC  
Max Humidity: 99% 3rd 
Min Humidity: 37% 23rd 
Mean Humidity: 74%  
 
Weather Data for Otter Valley, Devon. April 2021
  Temp oC Grass Hum (%) Soil oC (cm) Soil DP (oC) Wind (mph) Rain Air (hPa) W/m² UV Sun Frost Sea Observations
  Min Max Min Min Max 10 30 100 (cb) Min Max Max Ave Run mm Min Max Max Max Hours Hours Temp
1 6.8 18.2 5.6 67 98 10.1 9.4 9.3 0.0 6.0 12.5 16 2.7 64 0.0 1019 1025 621 3.3 4.9 0.0 10.0 Sunny intervals all day
2 4.6 14.0 3.9 57 88 9.9 9.9 9.4 0.0 2.4 7.9 19 5.0 119 0.0 1025 1031 651 4.5 11.6 0.0 9.9 Sunny intervals all day
3 -0.1 12.7 0.0 58 99 9.2 9.6 9.4 0.0 -1.1 5.7 17 3.1 75 0.0 1030 1034 893 4.5 6.9 0.0 9.8 Sunny intervals all day
4 -1.4 17.1 -0.6 52 97 8.8 9.2 9.4 0.0 -2.2 8.7 15 2.6 64 0.0 1023 1032 641 4.3 12.6 5.9 10.1 Sunny all day
5 6.1 11.5 -2.8 43 93 9.0 9.4 9.4 0.0 -4.3 6.8 26 6.0 143 0.0 1018 1025 923 5.4 8.2 0.0 9.8 Sunny intervals all day
6 -2.2 10.1 -6.1 52 93 8.0 8.7 9.4 0.0 -4.5 1.8 26 4.7 113 0.0 1022 1025 854 5.3 7.2 9.2 9.5 Sunny intervals all day
7 -2.3 9.8 -5.6 54 95 7.6 8.3 9.4 0.0 -3.9 4.0 17 2.5 60 0.0 1023 1026 607 5.3 3.7 7.3 9.3 Sunny intervals all day
8 -0.6 14.0 -4.4 63 95 7.8 8.3 9.4 0.0 -2.3 8.1 23 3.5 83 0.0 1019 1027 789 5.1 2.4 1.4 9.4 Sunny intervals all day
9 -0.6 14.4 -3.9 57 99 8.3 8.3 9.4 0.0 -1.6 7.0 13 1.6 38 0.0 1013 1019 755 4.3 5.2 2.8 9.6 Sunny intervals all day
10 4.7 13.4 2.2 53 94 8.7 8.9 9.4 0.0 1.2 6.2 16 3.8 92 0.0 1012 1014 800 4.1 6.3 0.0 9.6 Sunny intervals all day
11 -0.5 12.1 -2.8 42 98 8.4 8.7 9.4 0.0 -2.2 3.8 19 3.2 78 0.0 1014 1026 868 3.9 6.7 2.5 9.6 Sunny intervals all day
12 -1.5 13.2 -5.0 60 96 8.0 8.5 9.4 0.0 -3.2 7.5 19 2.8 68 1.4 1026 1031 915 4.3 7.2 7.4 9.5 Sunshine & light showers
13 -1.3 13.7 -3.3 60 98 8.3 8.5 9.4 0.0 -2.3 7.1 15 2.0 49 0.0 1032 1034 861 4.3 7.3 5.3 9.8 Sunny intervals all day
14 -1.2 13.5 -2.8 64 98 8.0 8.4 9.4 0.0 -1.9 9.0 11 1.6 39 0.0 1031 1033 810 3.6 4.8 6.4 9.9 Sunny intervals all day
15 -0.9 12.7 -3.3 54 98 8.2 8.3 9.3 0.0 -1.9 4.9 17 2.9 70 0.0 1031 1034 880 4.3 12.4 2.8 9.9 Sunny intervals all day
16 -1.8 12.9 -3.3 50 96 8.2 8.4 9.0 0.0 -2.7 4.3 14 2.3 56 0.0 1030 1032 941 4.5 6.4 7.5 10.1 Sunny intervals all day
17 -2.4 14.3 -5.0 45 96 8.0 8.3 8.9 0.0 -3.6 4.8 15 3.0 73 0.0 1027 1031 707 4.7 13.4 7.7 10.2 Sunny all day
18 -1.2 16.8 -3.3 46 95 8.4 8.5 8.9 0.0 -2.3 7.1 15 3.1 74 0.0 1023 1028 806 5.2 13.1 4.8 10.2 Sunny all day
19 -1.0 15.1 -3.3 54 97 8.8 8.8 8.9 0.0 -1.9 8.2 15 2.2 54 0.0 1019 1024 722 5.5 13.4 3.8 10.6 Sunny all day
20 -0.6 17.4 -2.8 42 98 9.0 8.9 9.2 0.0 -1.4 7.7 14 2.3 56 0.0 1016 1020 739 5.5 13.5 4.2 11.3 Sunny all day
21 3.6 16.8 -0.6 58 95 9.6 9.3 9.4 0.0 1.4 9.6 12 1.8 44 0.0 1018 1021 875 4.8 8.7 0.0 11.1 Sunny intervals all day
22 4.1 12.9 -1.1 57 95 9.7 9.4 9.4 0.0 1.2 7.6 15 3.0 72 0.0 1021 1026 732 5.3 13.6 0.0 10.9 Sunny all day
23 5.2 15.6 1.1 37 84 9.7 9.6 9.4 0.0 -1.4 7.8 18 4.9 118 0.0 1024 1027 753 5.6 13.7 0.0 10.8 Sunny all day
24 9.5 16.2 3.9 44 75 10.1 9.8 9.4 0.0 -0.5 7.2 21 6.0 145 0.0 1024 1026 766 6.2 13.8 0.0 10.8 Sunny all day
25 5.4 16.1 0.0 48 88 10.1 10.0 9.4 0.0 0.6 9.2 17 2.9 70 0.0 1023 1027 756 6.3 13.8 0.0 10.9 Sunny all day
26 3.4 15.5 -1.1 47 91 10.1 10.0 9.4 0.0 0.6 6.0 15 3.7 88 0.0 1015 1025 758 5.4 13.9 0.0 10.9 Sunny all day
27 -0.7 17.2 -3.3 52 97 10.0 10.1 9.6 0.0 -1.6 9.0 15 2.0 48 0.0 1006 1016 915 5.4 8.4 2.3 11.1 Sunny all day
28 6.1 12.9 6.1 67 96 10.2 10.0 10.0 0.0 4.6 8.7 22 4.0 97 9.6 1004 1009 802 4.7 3.2 0.0 10.8 Early rain the sunny intervals
29 0.6 13.0 -2.2 49 98 9.9 10.0 10.0 0.0 -0.4 5.4 15 3.0 76 0.0 1009 1015 753 5.1 7.1 0.0 10.9 Sunny intervals all day
30 0.2 12.9 -1.7 56 97 9.6 9.9 10.0 0.0 -0.9 6.0 15 1.7 38 0.4 1015 1016 886 4.3 5.1 0.0 10.9 Sunny ints and showers
1.3 14.2 -1.5 53 95 9.0 9.1 9.4 0.0 -1.0 7.0 17 3.1 2261 11.4 1020 1025 793 4.8 268.4 81.2 10.2  
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