Rainfall – Ver Valley Society

The flow in the River Ver is dependent on rainfall to recharge the aquifer, from which water is pumped to supply the needs of the district. Recharge largely happens in the winter and early spring; any rainfall during the summer has little effect as surface water evaporates and is used up by growing vegetation. Although after heavy rains, at any time of year, the run-off can cause short-term improvement in flow, it takes many weeks for any effect to be measured in aquifer levels or to have any long-term effect on the river.

It is therefore important for the Ver Valley Society to monitor rainfall figures regularly throughout the year and we do this with the help of Rothamsted Research Station (see tables below). 2008 was the wettest year since 2000. In 2009 rainfall was nearly 10% above average and as the Bow Bridge Pumping Station was shut down until August good flows were recorded in the first half of that year and the aquifer came back to average values.

Subsequent rainfall in 2009 and 2010 generally fell below average but flows remained moderate. However poor winter rains in 2011 mean the river was exceptionally low by the end of 2011. However the total rainfall for 2012 was the highest ever recorded at Rothamsted and their records go back to 1870. Unusually the aquifer level increased over the summer months. At the end of 2012 it was over 3 metres above average and the river was flowing north of Redbourn.

2013 rainfall was just above average with storms in December and in 2014 January rainfall was highest monthly total ever recorded since Rothamsted started recording in 1870. That summer saw a very high aquifer and good flows as a result but the winter of 2014/2015 had poor rainfall and the subsequent dry warm summer and autumn meant the aquifer dropped to well below average and poor flows resulted. Early winter 2015 was very warm with only poor rainfall but better rainfall at the beginning of 2016 helped some recovery of the aquifer and reasonable flows have been maintained through the summer after a wet June. From 2017 through to March 2019 has been relatively dry particularly in the winter months and with the very low aquifer the Ver has been dry for many months north of Redbourn.

With above average rainfall through the 2019/20 winter the aquifer was high enough to get flow through Redbourn for the first time since the summer of 2016. Rainfall has continued to be above average through to 2021 so in the Spring of 2021 the aquifer was the highest level since 2001 and flow in the Ver the best also since 2001.

See rainfall figures below. We are grateful to Rothamsted Research who supply these figures to the Society each month. If you wish to use these figures you should seek permission from Rothamsted Research.

Month 2025	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	74.5	74.1	+0.4	100.5%
February	51.3	56.9	-5.6	90%
March	6.30	47.1	-40.8	13.4%
April	27.7	54.0	-26.3	51.3%
May	19.6	53.3	-33.7	36.8%
June
July
August
September
October
November
December

Totals	179.4	285.5	–72.3	63%

Month 2024	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	72.6	74.1	-1.5	98%
February	130.0	57.0	73.0	228%
March	90.0	47.1	42.9	191%
April	67.4	54.0	13.4	134%
May	114.8	53.3	61.5	215%
June	21.5	54.8	-33.3	39%
July	91.0	55.5	35.5	162%
August	23.2	72.0	-48.8	32%
September	185.2	57.7	+127.5	321%
October	62.0	81.3	-19.3	76%
November	66.7	81.2	-14.5	82%
December	68.1	75.6	-7.5	90%

Totals	992.5	763.6	228.97	130%

Month 2023	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	79.6	74.1	+5.5	107%
February	5.7	57.0	-51.3	10%
March	117.2	47.1	+70.1	249%
April	65.0	54.0	+11.0	120%
May	48.9	53.3	-4.4	92%
June	16.0	54.9	-38.9	29%
July	97.8	55.5	42.3	176%
August	50.5	71.6	-21.5	70%
September	60.3	57.8	2.5	104%
October	100.9	81.3	19.5	124%
November	75.6	81.2	-5.6	92%
December	101.3	75.7	+25.7	134%

Totals	818.6	763.8	55.1	107%

Month 2022	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	23.4	74.1	-50.7	31.6%
February	79.0	57.0	+22.0	138.6%
March	34.1	46.4	-12.9	73.5%
April	20.8	54.0	-33.2	38.5%
May	33.9	53.2	-19.3	63.7%
June	43.8	54.8	-11.0	79.9%
July	11.4	55.1	-43.7	21.0%
August	41.4	71.8	-30.6	58.0%
September	77.9	67.8	+20.1	134.0%
October	101.0	81.3	+19.7	124.2%
November	131.7	81.2	+50.4	162.2%
December	67.9	75.7	-7.7	89.7%

Totals	666.7	763.8	-97.1	87.3%

Month 2021	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	113.6	74.1	+39.5	153%
February	45.8	56.9	-11.1	80%
March	27.6	47.1	-19.5	59%
April	1.3	54.0	-52.4	2.4%
May	94.4	53.3	+41.1	177%
June	77.6	54.8	+22.8	136%
July	51.0	55.5	-4.5	92%
August	37.0	72.0	-35.0	51%
September	54.1	76.8	-3.6	99%
October	104.8	81.3	+23.5	129%
November	19.2	81.2	-62.0	23.6%
December	76.3	75.7	+0.6	100.8%

Totals	703.0	765.6	-60.6	92.1%

Month 2020	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	79.8	70.0	+9.8	114%
February	127.0	50.1	+76.9	253%
March	43.8	50.8	-7.0	87%
April	51.4	55.1	-3.7	93%
May	3.2	54.7	-51.5	6%
June	87.4	53.3	+34.1	164%
July	81.2	49.9	+31.3	163%
August	172	63.7	+108.3	270%
September	32.8	57.6	-24.8	57%
October	198.4	81.7	+116.7	243%
November	57.4	76.7	-19.3	75%
December	98.4	69.5	28.9	141%

TOTALS	1032.8	731.0	+301.8	141%

Month 2019	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	34.8	70.0	-35.2	50%
February	43.2	50.1	-6.9	86%
March	60.4	50.8	+9.6	119%
April	13.2	55.1	-41.9	25%
May	42.8	54.7	-11.9	78%
June	70.8	53.3	+17.5	133%
July	45.0	49.9	-4.47	96%
August	45.2	63.7	-18.5	71%
September	75.0	57.6	+17.4	130%
October	109.6	81.7	+27.9	134%
November	91.0	76.7	+14.4	118%
December	111.6	69.5	+42.1	162%

TOTALS	742.6	733.0	+9.6	101%

Month 2018	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	76.1	69.6	6.5	109.4%
February	48.4	50.1	-1.7	96.5%
March	78.5	50.8	27.7	154.5%
April	74.8	55.1	19.7	135.8%
May	61.9	54.7	7.2	113.2%
June	3.7	53.3	-49.6	6.9%
July	15.1	49.9	-34.8	30.2%
August	64.0	63.7	0.3	100.4%
September	51.0	57.6	-6.6	88.5%
October	71.0	81.67	-10.67	86.9%
November	63.8	76.63	-12.83	83.25%
December	75.0	69.6	5.48	107.31%

TOTALS	683.3	732.7	-49.4	93.3%

Month 2017	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	70.2	70.0	0.2	100.3%
February	38.7	50.1	-11.4	77.2%
March	40.4	50.8	-10.4	79.5%
April	10.9	55.1	-44.2	19.8%
May	70.5	54.7	15.8	128.9%
June	39.1	53.2	-14.1	73.5%
July	72.6	49.9	22.7	145.5%
August	66.6	63.7	2.9	104.5%
September	86.9	57.6	29.3	150.8%
October	31.2	81.8	-50.6	38.1%
November	53.6	76.7	-23.1	69.9%
December	110.8	69.6	41.3	159.3%

TOTALS	691.5	733.2	-41.7	94.3%

Month 2016	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	92.3	70.0	22.3	131.9%
February	46.9	50.2	-3.3	93.5%
March	84.3	50.8	33.5	166.0%
April	62.0	55.0	7.0	112.6%
May	39.4	54.7	-15.3	72.0%
June	84.8	53.2	31.6	159.3%
July	27.1	49.9	-22.8	54.3%
August	30.1	63.7	-33.6	47.3%
September	70.3	57.6	12.7	122.0%
October	30.1	81.7	-51.6	36.9%
November	85.7	76.7	9.0	111.8%
December	26.2	69.5	-43.3	37.7%

TOTALS	679.2	732.9	-53.7	92.7%

Month 2015	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	81.9	70.0	11.9	117.1%
February	54.6	50.2	4.4	108.8%
March	26.1	50.8	-24.7	51.4%
April	31.0	55.1	-24.1	56.3%
May	68.4	54.7	13.8	125.2%
June	26.7	53.3	-26.6	50.1%
July	132.6	49.9	82.7	265.8%
August	83.2	63.7	19.5	130.6%
September	45.5	57.7	-12.2	78.9%
October	64.6	81.6	-17.0	79.1%
November	84.0	76.6	7.4	109.7%
December	81.8	69.5	12.3	117.7%

TOTALS	780.4	732.9	47.5	106.5%

Month 2014	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	176.2	69.9	106.3	252.1%
February	141.9	50.1	91.8	283.2%
March	28.2	50.8	-22.6	55.5%
April	31.5	54.1	-22.6	58.3%
May	82.8	54.7	28.1	151.5%
June	30.5	53.3	-22.8	57.3%
July	36.9	49.9	-13.0	73.9%
August	113.3	63.7	49.6	177.8%
September	14.8	57.6	-42.8	25.7%
October	95.7	81.7	14.1	117.2%
November	108.2	76.6	31.6	141.2%
December	64.0	69.6	-5.6	92.0%

TOTALS	924.0	731.8	192.2	126.3%

Month 2013	Actual Rainfall Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	62.8	70.0	-7.2	89.8%
February	43.4	50.1	-6.7	86.6%
March	83.1	50.8	32.3	163.6%
April	32.8	55.1	-22.3	59.5%
May	56.0	54.7	1.2	102.4%
June	24.6	53.3	-28.7	46.2%
July	47.4	50.1	-2.5	94.6%
August	57.5	63.7	-6.2	90.2%
September	50.2	57.6	-7.4	87.2%
October	108.8	81.7	27.1	133.1%
November	59.5	76.6	-17.1	77.6%
December	123.1	69.5	53.6	177.1%

TOTALS	749.2	733.1	16.1	102.2%

Month 2012	Actual Rainfall Millimetres	Average Rainfall In Millimetres	=+/- mm Average	Percent Average
January	58.0	70.0	-12.0	82.9%
February	24.7	50.3	-25.6	49.1%
March	34.7	50.8	-16.1	68.3%
April	168.6	55	113.6	306.4%
May	52.6	54.7	-2.1	96.2%
June	166.5	53.3	113.2	312.4%
July	128.4	49.8	78.6	257.7%
August	54.9	63.7	-8.8	86.2%
September	40.4	57.7	-17.3	70.1%
October	115.8	81.7	34.1	141.8%
November	100.4	76.6	23.8	131.1%
December	114.2	69.5	44.7	164.2%

TOTALS	1059.2	733.1	326.1	144.5%

Month 2011	Actual Rainfall Millimetres	Average Rainfall In Millimetres	=+/- mm Average	Percent Average
January	84.6	70.0	14.6	120.9%
February	56.8	50.1	6.7	113.3%
March	10.0	50.8	-40.8	19.7%
April	5.2	55.1	-49.9	9.4%
May	23.6	54.7	-31.1	43.2%
June	83.0	53.3	29.7	155.8%
July	44.6	49.9	-5.3	89.4%
August	81.2	63.7	17.5	127.4%
September	38.4	57.6	-19.2	66.6%
October	25.2	81.7	-56.5	30.9%
November	36.4	76.6	-40.2	47.5%
December	82.4	69.5	12.9	118.5%

TOTALS	571.4	732.9	-161.5	78.0%

Month 2010	Actual Rainfall (2010) Millimetres	Average Rainfall In Millimetres	=+/- mm Average	Percent Average
January	47.3	69.7	-22.4	67.9%
February	77.2	48.8	28.4	158.2%
March	45.2	53.9	-8.7	83.8%
April	18.7	53.4	-34.7	35.0%
May	38.4	49.7	-11.3	77.3%
June	23.5	60.2	-36.7	39.0%
July	31.6	42.1	-10.5	75.1%
August	127.6	53.5	74.1	238.3%
September	59.7	61.0	-1.3	97.9%
October	84.9	74.7	10.2	113.7%
November	54.9	66.3	-11.4	82.8%
December	35.3	70.1	-34.8	50.4%

TOTALS	644.3	703.4	-59.1	91.6%

Month 2009	Actual Rainfall (2009) Millimetres	Average Rainfall In Millimetres	+/- mm Average	Percent Average
January	70.4	69.7	0.7	101.0%
February	73.9	48.8	25.1	151.4%
March	37.3	53.9	-16.6	69.2%
April	46.7	53.5	-6.8	87.3%
May	24.8	49.7	-24.9	49.9%
June	68.1	60.2	7.9	113.1%
July	73.3	42.1	31.2	174.1%
August	63.4	53.7	9.7	118.1%
September	15.9	61.0	-45.1	26.1%
October	39.1	74.7	-35.6	52.4%
November	146.1	66.2	79.9	220.6%
December	105.2	70.1	35.1	150.0%

TOTALS	764.2	703.6	60.6	108.6%

Month 2008	Actual Rainfall (2008) Millimetres	Average Rainfall In Millimetres	=+/- mm Average	Percent Average
January	103.2	69.7	33.5	148.1%
February	21.9	48.8	-26.9	44.9%
March	108.5	53.9	54.6	201.3%
April	53.5	53.5	0.0	100.0%
May	87.0	49.7	37.3	175.1%
June	35.3	60.2	-24.9	58.6%
July	90.3	42.0	48.3	215.0%
August	107.8	53.7	54.1	200.7%
September	66.2	61.0	5.2	108.5%
October	74.3	74.7	-0.4	99.5%
November	91.1	66.2	24.9	137.6%
December	42.0	70.1	-28.1	59.9%

TOTALS	881.1	703.5	177.6	125.2%

Month 2007	Actual Rainfall (2007) Millimetres	Average Rainfall In Millimetres	=+/- mm Average	Percent Average
January	91.6	69.7	21.9	131.4%
February	97.44	48.6	48.84	200.5%
March	57.6	53.9	3.7	106.9%
April	2.8	53.5	-50.7	5.2%
May	135.8	49.7	86.1	273.2%
June	72.4	60.2	12.2	120.3%
July	86.8	44.6	42.2	194.6%
August	64.6	53.9	10.7	119.9%
September	29.2	61.0	-31.8	47.9%
October	57.1	74.7	-17.6	76.4%
November	80.0	66.2	13.8	120.8%
December	67.1	70.1	-3.0	95.7%

TOTALS	842.44	706.1	136.34	119.3%

Month 2006	Actual Rainfall (2006) Millimetres	Average Rainfall Millimetres	=+/- mm Average!	Percent Average
January	29.2	69.7	-40.5	41.9%
February	41.4	48.8	-7.4	84.8%
March	49.5	53.9	-4.4	91.8%
April	51.0	53.5	-2.5	95.3%
May	89.0	49.7	39.3	179.1%
June	15.0	60.2	-45.2	24.9%
July	35.6	42.1	-6.5	84.6%
August	110.0	53.7	56.3	204.8%
September	54.2	61.0	-6.8	88.9%
October	105.0	74.7	30.3	140.6%
November	104.4	66.2	38.2	157.7%
December	95.0	74.1	20.9	128.2%

TOTALS	779.3	707.6	71.7	110.1%

Month 2005	Actual Rainfall (2005) Millimetres	Average Rainfall In Millimetres	=+/- mm Average	Percent Average
January	33.8	69.7	-35.9	48.5%
February	36.2	48.8	-12.6	74.2%
March	43.2	53.4	-10.2	80.9%
April	65.6	53.5	12.1	122.6%
May	44.4	49.7	-5.3	89.3%
June	44.0	60.2	-16.2	73.1%
July	39.0	42.1	-3.1	92.6%
August	58.6	53.7	4.9	109.1%
September	65.0	61.0	4.0	106.6%
October	88.4	74.7	13.7	118.3%
November	53.8	66.8	-13.0	80.5%
December	53.0	74.5	-21.5	71.1%

TOTALS	625.0	708.1	-83.1	88.3%