Monthly Solar Irradiance Records
The following table lists the mean daily irradiance for each month at Brookhaven National Laboratory since 1994.
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average
1994 72.2 116.7 147.7 207.9 246.9 265.2 259.8 193.4 187.5 152.3 92.6 72.5 167.9
1995 74.9 108.1 182.7 231.9 281.6 168.3 97.4 301.1 290.0 151.1 85.5 77.4 170.8
1996 63.2 113.9 171.6 193.7 242.0 239.0 222.8 227.1 158.6 145.2 92.9 52.5 160.2
1997 80.1 119.4 152.4 226.6 261.3 283.7 288.6 225.2 180.4 145.4 78.4 70.8 176.0
1998 72.4 113.4 146.5 215.0 243.3 283.5 268.4 255.5 204.3 139.5 98.3 64.7 175.4
1999 73.5 114.4 195.3 223.2 249.6 285.3 270.1 223.9 219.4 156.0 97.1 77.6 182.1
2000 82.7 122.4 182.8 171.7 278.3 267.5 265.5 212.8 208.4 194.6 120.7 81.9 182.4
2001 81.7 125.1 148.3 220.6 289.4 281.5 284.2 227.5 202.6 159.3 105.9 74.7 183.4
2002 78.0 162.4 161.2 230.5 264.4 289.4 291.7 271.6 191.7 122.8 78.8 70.3 184.4
2003 83.9 74.3 174.1 191.8 190.4 262.6 249.8 294.6 175.3 118.8 80.4 58.8 162.9
2004 nan nan nan nan nan nan nan nan nan nan nan nan nan
2005 nan nan nan nan nan nan nan nan nan nan nan nan nan
2006 nan nan nan nan nan nan nan nan nan nan nan nan nan
2007 nan nan nan nan nan nan nan nan nan nan nan nan nan
2008 nan nan nan nan nan nan nan nan nan nan nan nan nan
2009 nan nan nan nan nan nan nan nan nan nan nan nan nan
2010 nan nan nan nan nan nan nan nan nan nan nan nan nan
2011 86.2 121.1 177.5 172.6 223.6 254.2 276.7 223.7 130.0 130.3 97.5 75.2 164.1
2012 91.5 126.5 163.7 254.3 199.2 268.3 249.0 231.8 179.6 110.0 92.8 59.8 168.9
2013 82.6 109.8 163.0 243.9 236.7 256.7 239.0 210.4 189.8 128.6 96.1 60.9 168.1
2014 79.9 120.8 159.1 223.3 237.1 276.5 262.6 238.7 184.8 115.6 86.3 56.4 170.1
2015 79.6 119.2 160.5 212.3 261.8 232.9 252.1 250.5 200.1 137.5 88.2 57.2 171.0
2016 93.2 106.1 174.7 220.6 208.9 285.8 258.1 234.1 165.0 127.4 98.6 68.8 170.1
2017 64.0 120.3 160.2 185.9 216.8 253.8 239.4 219.3 171.1 127.5 85.2 63.5 158.9
2018 83.9 93.9 158.7 188.4 206.2 258.4 254.8 215.7 137.8 115.5 78.3 66.1 154.8
2019 77.0 112.0 172.0 180.6 218.7 246.6 276.5 222.6 193.5 109.5 89.5 57.3 163.0
2020 78.9 105.8 152.4 177.5 259.2 271.1 249.7 211.5 180.8 105.3 86.3 60.7 161.6
2021 81.5 93.0 179.7 218.0 251.3 262.9 217.5 195.2 181.1 122.0 99.4 61.5 163.6
2022 79.7 119.9 157.8 218.8 223.1 261.9 265.9 241.0 186.0 123.5 97.4 73.9 170.7
2023 59.9 113.1 164.4 185.7 288.2 235.1 250.7 210.6 164.3 131.8 99.2 78.7 165.1
2024 62.5 126.3                     94.4
                           
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Totals
Average 78.3 114.4 165.5 208.5 242.5 260.4 251.8 232.1 186.2 133.5 92.4 67.0 169.4
                           
Maximum 93.2 162.4 195.3 254.3 289.4 289.4 291.7 301.1 290.0 194.6 120.7 81.9 184.4
Minimum 59.9 74.3 146.5 171.7 190.4 168.3 97.4 193.4 130.0 105.3 78.3 52.5 154.8
nan indicates missing data
Values in fields filled in yellow are the monthly averages inserted because of partially missing data.
The average then changes with addition of this value.