Overview Realtime Historical Map View
Heat Advisory
2026-07-15T20:00:00-04:00

* WHAT...Heat index values around 105 expected. * WHERE...Portions of north central and western Maryland, northwest and western Virginia, and eastern and panhandle West Virginia. * WHEN...From 11 AM to 8 PM EDT Wednesday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.

Potomac River At Hancock, Md Historical Data

Historical Data


Streamflow Range


Date Average 2026 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011
01-01 5312.75
01-02 5124.58
01-03 5700.67
01-04 5289.92
01-05 4718.5
01-06 4339.42
01-07 4169.92
01-08 3748.5
01-09 3433.58
01-10 3687.36
01-11 5172.27
01-12 5013.18
01-13 5910.0
01-14 6860.91
01-15 6000.0
01-16 5064.55
01-17 5392.5
01-18 5194.55
01-19 4621.82
01-20 4117.27
01-21 5978.0
01-22 5254.44
01-23 4540.0
01-24 3428.58
01-25 4524.7
01-26 6842.56
01-27 7069.0
01-28 7476.25
01-29 8226.67
01-30 7710.0
01-31 6020.0
02-01 7384.0
02-02 6566.67
02-03 5808.0
02-04 6830.0
02-05 8076.15
02-06 6073.33
02-07 6903.08
02-08 7886.92
02-09 7488.46
02-10 6319.23
02-11 5495.38
02-12 5250.77
02-13 5665.38
02-14 6880.0
02-15 6280.0
02-16 5592.31
02-17 5920.91
02-18 7726.36
02-19 7013.33
02-20 6450.0
02-21 7388.46
02-22 7141.67
02-23 8660.0
02-24 8156.92
02-25 9095.0
02-26 9241.67
02-27 9017.69
02-28 7365.38
02-29 5785.0
03-01 8633.08
03-02 12255.38
03-03 9643.85
03-04 8463.08
03-05 7976.92
03-06 6710.0
03-07 6880.71
03-08 6146.43
03-09 5633.57
03-10 6241.43
03-11 7452.86
03-12 7390.71
03-13 7372.14
03-14 6931.43
03-15 6304.29
03-16 6105.71
03-17 5462.14
03-18 5059.29
03-19 4940.0
03-20 4790.71
03-21 4845.33
03-22 4886.43
03-23 4949.33
03-24 4580.0
03-25 4412.0
03-26 4816.0
03-27 4998.67
03-28 4688.67
03-29 4661.33
03-30 4972.67
03-31 5100.0
04-01 4959.33
04-02 5494.0
04-03 6881.33
04-04 8846.67
04-05 7740.0
04-06 6226.0
04-07 5996.0
04-08 6060.67
04-09 6218.0
04-10 5508.0
04-11 5509.33
04-12 5452.86
04-13 5822.86
04-14 5627.14
04-15 5560.77
04-16 5444.62
04-17 6766.92
04-18 7375.38
04-19 5570.77
04-20 4999.23
04-21 6662.14
04-22 6173.57
04-23 5125.71
04-24 4547.14
04-25 4285.0
04-26 4319.29
04-27 4538.57
04-28 5142.14
04-29 4834.29
04-30 4747.14
05-01 7568.0
05-02 7342.14
05-03 6594.29
05-04 5905.33
05-05 6509.33
05-06 9466.0
05-07 9667.33
05-08 11540.67
05-09 11668.0
05-10 8817.86
05-11 7573.33
05-12 6586.0
05-13 6864.67
05-14 8302.67
05-15 7450.71
05-16 7076.43
05-17 10505.21
05-18 10364.0
05-19 12944.27
05-20 11132.64
05-21 7731.2
05-22 6180.0
05-23 6218.67
05-24 7194.0
05-25 6153.33
05-26 5455.33
05-27 5562.0
05-28 5799.33
05-29 7962.0
05-30 6886.0
05-31 5648.0
06-01 5575.0
06-02 4731.33
06-03 4486.67
06-04 9512.0
06-05 6145.71
06-06 4191.43
06-07 3942.36
06-08 3314.27
06-09 3029.0
06-10 3467.8
06-11 3599.33
06-12 4597.29
06-13 4156.29
06-14 4152.36
06-15 3375.67
06-16 3191.73
06-17 2869.73
06-18 3459.47
06-19 3339.36
06-20 3510.36
06-21 3294.07
06-22 3931.64
06-23 4480.57
06-24 4081.79
06-25 3484.43
06-26 2961.43
06-27 2472.21
06-28 3499.5
06-29 3966.14
06-30 3120.29
07-01 2366.57
07-02 2542.86
07-03 2247.07
07-04 2022.29
07-05 1821.87
07-06 1844.33
07-07 1854.14
07-08 1917.0
07-09 2229.36
07-10 2038.2
07-11 1839.33
07-12 1764.4
07-13 1716.8
07-14 1867.2
07-15 1754.0
07-16 1610.93
07-17 1632.64
07-18 1686.93
07-19 1476.71
07-20 1488.21
07-21 1491.71
07-22 1467.07
07-23 1398.79
07-24 1829.21
07-25 1577.86
07-26 1578.43
07-27 1652.0
07-28 1316.64
07-29 1268.14
07-30 1413.93
07-31 2307.93
08-01 1878.38
08-02 2158.0
08-03 2003.64
08-04 2361.5
08-05 2036.71
08-06 1718.0
08-07 1495.5
08-08 1493.0
08-09 1482.92
08-10 1445.0
08-11 1439.14
08-12 1422.57
08-13 1293.43
08-14 1300.64
08-15 1413.07
08-16 1316.23
08-17 1254.77
08-18 1496.25
08-19 1333.77
08-20 1298.38
08-21 1128.77
08-22 1333.75
08-23 1568.71
08-24 1303.46
08-25 1246.92
08-26 1263.14
08-27 1195.0
08-28 997.79
08-29 971.0
08-30 1002.71
08-31 1196.29
09-01 1123.36
09-02 2082.93
09-03 2607.71
09-04 1647.57
09-05 1418.57
09-06 1211.36
09-07 1285.57
09-08 2576.14
09-09 2096.79
09-10 5104.57
09-11 5858.21
09-12 3250.14
09-13 2706.86
09-14 2343.71
09-15 1863.71
09-16 1636.07
09-17 1513.07
09-18 1360.36
09-19 3021.29
09-20 2280.07
09-21 1812.21
09-22 1672.08
09-23 1415.43
09-24 1704.36
09-25 2023.0
09-26 3692.79
09-27 3129.29
09-28 2914.43
09-29 6046.0
09-30 3792.46
10-01 1361.77
10-02 1346.0
10-03 1851.08
10-04 1771.46
10-05 2354.43
10-06 2075.64
10-07 1780.21
10-08 1532.36
10-09 1397.07
10-10 1325.07
10-11 1365.21
10-12 1345.14
10-13 1535.36
10-14 1524.86
10-15 1578.0
10-16 1743.43
10-17 1722.54
10-18 1511.07
10-19 1360.43
10-20 1247.57
10-21 1168.71
10-22 1129.43
10-23 1093.21
10-24 1056.21
10-25 1027.5
10-26 1016.21
10-27 988.29
10-28 1013.93
10-29 1168.71
10-30 1778.64
10-31 5308.36
11-01 3347.36
11-02 2765.29
11-03 2424.36
11-04 2210.64
11-05 1683.62
11-06 2182.31
11-07 2116.77
11-08 2115.38
11-09 2209.38
11-10 2799.23
11-11 2851.31
11-12 2275.69
11-13 2769.92
11-14 2985.07
11-15 2845.69
11-16 2397.21
11-17 2376.62
11-18 2592.54
11-19 2714.31
11-20 2523.08
11-21 2725.86
11-22 2807.54
11-23 2994.43
11-24 4132.62
11-25 3349.15
11-26 3182.93
11-27 2825.79
11-28 2522.57
11-29 2355.71
11-30 2269.0
12-01 2592.5
12-02 2545.43
12-03 2672.21
12-04 2852.14
12-05 2575.29
12-06 2422.08
12-07 2266.07
12-08 4409.21
12-09 3256.15
12-10 3883.86
12-11 3199.64
12-12 3094.43
12-13 2859.79
12-14 2619.31
12-15 2440.92
12-16 5314.5
12-17 8473.0
12-18 5741.33
12-19 5188.08
12-20 4123.83
12-21 3798.73
12-22 4550.5
12-23 5971.46
12-24 5353.38
12-25 5175.92
12-26 5675.92
12-27 5598.83
12-28 4558.46
12-29 4810.91
12-30 5523.33
12-31 6364.17

Annual Peak Streamflow


Seasonal Comparison


Oceanic Nino Index