Overview Realtime Historical Map View
Extreme Heat Warning
2026-08-16T21:00:00-05:00

* WHAT...Dangerously hot conditions with heat index values of 105 to 110 degrees. * WHERE...Portions of south central and southwest Illinois and central, east central, and southeast Missouri. * WHEN...Until 9 PM CDT this evening. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.

Gravois Creek Near Mehlville, Mo 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 10.17
01-02 8.64
01-03 28.17
01-04 7.1
01-05 4.98
01-06 4.31
01-07 4.33
01-08 5.9
01-09 20.09
01-10 84.82
01-11 307.07
01-12 15.72
01-13 47.38
01-14 8.21
01-15 19.7
01-16 6.95
01-17 5.91
01-18 140.18
01-19 32.17
01-20 6.15
01-21 5.4
01-22 5.09
01-23 88.06
01-24 21.57
01-25 9.98
01-26 25.21
01-27 8.69
01-28 8.83
01-29 5.96
01-30 75.47
01-31 21.4
02-01 7.46
02-02 23.21
02-03 6.91
02-04 45.54
02-05 8.32
02-06 24.89
02-07 37.52
02-08 7.62
02-09 57.05
02-10 17.3
02-11 8.48
02-12 13.22
02-13 10.21
02-14 4.97
02-15 23.91
02-16 16.12
02-17 106.21
02-18 9.52
02-19 7.43
02-20 8.48
02-21 48.92
02-22 9.95
02-23 9.45
02-24 40.5
02-25 16.3
02-26 14.39
02-27 8.51
02-28 31.55
02-29 4.41
03-01 6.46
03-02 8.81
03-03 41.69
03-04 12.25
03-05 18.64
03-06 7.43
03-07 89.52
03-08 7.82
03-09 6.88
03-10 19.61
03-11 12.27
03-12 9.38
03-13 22.4
03-14 39.56
03-15 173.79
03-16 23.44
03-17 9.92
03-18 122.14
03-19 12.52
03-20 13.96
03-21 7.51
03-22 11.01
03-23 7.66
03-24 127.36
03-25 57.2
03-26 31.92
03-27 14.98
03-28 27.77
03-29 11.72
03-30 25.52
03-31 35.86
04-01 12.89
04-02 72.83
04-03 34.27
04-04 91.73
04-05 122.17
04-06 19.41
04-07 9.22
04-08 36.29
04-09 24.39
04-10 13.01
04-11 107.27
04-12 10.7
04-13 26.51
04-14 87.56
04-15 12.58
04-16 180.03
04-17 10.38
04-18 56.71
04-19 17.64
04-20 13.07
04-21 27.74
04-22 8.46
04-23 6.75
04-24 26.07
04-25 52.22
04-26 14.35
04-27 31.27
04-28 27.6
04-29 168.4
04-30 18.28
05-01 68.26
05-02 18.67
05-03 48.59
05-04 74.19
05-05 45.58
05-06 16.56
05-07 13.18
05-08 16.22
05-09 26.77
05-10 19.9
05-11 8.79
05-12 10.14
05-13 9.13
05-14 10.49
05-15 32.95
05-16 12.38
05-17 31.23
05-18 54.36
05-19 18.44
05-20 15.36
05-21 136.68
05-22 20.26
05-23 8.07
05-24 11.89
05-25 17.46
05-26 17.32
05-27 9.73
05-28 22.94
05-29 11.43
05-30 10.4
05-31 56.77
06-01 237.36
06-02 13.94
06-03 6.28
06-04 5.13
06-05 18.63
06-06 9.06
06-07 8.14
06-08 14.23
06-09 6.64
06-10 66.28
06-11 34.77
06-12 18.22
06-13 7.01
06-14 5.98
06-15 9.82
06-16 5.32
06-17 19.08
06-18 39.31
06-19 12.59
06-20 13.14
06-21 5.98
06-22 9.13
06-23 13.0
06-24 13.76
06-25 5.72
06-26 27.21
06-27 22.75
06-28 18.48
06-29 7.65
06-30 19.83
07-01 10.47
07-02 14.73
07-03 9.61
07-04 11.04
07-05 6.53
07-06 5.25
07-07 8.91
07-08 23.24
07-09 49.82
07-10 17.49
07-11 13.27
07-12 4.76
07-13 29.46
07-14 8.02
07-15 38.06
07-16 8.34
07-17 68.07
07-18 12.89
07-19 4.23
07-20 22.0
07-21 5.92
07-22 18.58
07-23 6.35
07-24 4.3
07-25 4.18
07-26 65.63
07-27 5.95
07-28 6.86
07-29 6.58
07-30 14.47
07-31 6.73
08-01 6.66
08-02 5.04
08-03 40.64
08-04 178.63
08-05 7.71
08-06 10.3
08-07 5.99
08-08 7.6
08-09 73.9
08-10 6.69
08-11 21.8
08-12 4.62
08-13 18.94
08-14 34.46
08-15 6.81
08-16 25.37
08-17 18.4
08-18 5.92
08-19 4.11
08-20 3.67
08-21 6.08
08-22 82.57
08-23 8.21
08-24 4.63
08-25 3.55
08-26 16.82
08-27 12.99
08-28 5.62
08-29 4.19
08-30 3.4
08-31 6.11
09-01 69.48
09-02 36.7
09-03 7.41
09-04 4.02
09-05 23.05
09-06 5.18
09-07 3.49
09-08 45.79
09-09 10.38
09-10 67.74
09-11 7.47
09-12 3.82
09-13 3.2
09-14 2.7
09-15 7.04
09-16 3.38
09-17 15.87
09-18 3.38
09-19 10.62
09-20 3.54
09-21 5.09
09-22 9.24
09-23 4.15
09-24 16.46
09-25 3.83
09-26 25.93
09-27 5.34
09-28 6.76
09-29 7.13
09-30 5.58
10-01 2.11
10-02 17.5
10-03 21.72
10-04 5.23
10-05 2.76
10-06 4.51
10-07 2.34
10-08 2.94
10-09 2.04
10-10 53.59
10-11 10.35
10-12 3.27
10-13 3.54
10-14 3.79
10-15 15.43
10-16 3.44
10-17 2.32
10-18 7.38
10-19 104.24
10-20 34.05
10-21 10.48
10-22 2.72
10-23 10.12
10-24 2.8
10-25 10.95
10-26 11.1
10-27 10.74
10-28 7.58
10-29 29.25
10-30 35.88
10-31 6.38
11-01 15.85
11-02 4.69
11-03 16.64
11-04 3.62
11-05 115.43
11-06 24.33
11-07 7.3
11-08 4.15
11-09 6.43
11-10 3.14
11-11 3.86
11-12 23.46
11-13 2.87
11-14 2.62
11-15 32.85
11-16 3.99
11-17 10.47
11-18 3.43
11-19 4.52
11-20 2.73
11-21 6.07
11-22 64.38
11-23 4.99
11-24 10.13
11-25 24.4
11-26 4.99
11-27 42.48
11-28 4.14
11-29 5.73
11-30 90.65
12-01 9.52
12-02 5.06
12-03 3.67
12-04 3.77
12-05 10.43
12-06 47.35
12-07 4.61
12-08 3.42
12-09 3.48
12-10 3.12
12-11 5.23
12-12 17.5
12-13 2.75
12-14 43.85
12-15 39.58
12-16 6.68
12-17 5.98
12-18 14.12
12-19 3.94
12-20 26.03
12-21 5.39
12-22 6.93
12-23 9.9
12-24 6.26
12-25 4.01
12-26 4.54
12-27 279.04
12-28 138.35
12-29 78.6
12-30 20.53
12-31 6.35

Annual Peak Streamflow


Seasonal Comparison


Oceanic Nino Index