Average Temperature1 Wetting Period (hr)2 Incubation
Period (days)3
F C   Low   Medium   High  
78 25.6 13 17 26 ---
77 25 11 14 21 ---
76 24.4 9.5 12 19 ---
63-75 17.2-23.9 9 12 18 9
62 16.7 9 12 19 10
61 16.1 9 13 20 10
60 15.6 9.5 13 20 11
59 15 10 13 21 12
58 14.4 10 14 21 12
57 13.9 10 14 22 13
56 13.3 11 15 22 13
55 12.8 11 16 24 14
54 12.2 11.5 16 24 14
53 11.7 12 17 25 15
52 11.1 12 18 26 15
51 10.6 13 18 27 16
50 10 14 19 29 16
49 9.4 14.5 20 30 17
48 8.9 15 20 30 17
47 8.3 15 23 35 ---
46 7.8 16 24 37 ---
45 7.2 17 26 40 ---
44 6.6 19 28 43 ---
43 6.1 21 30 47 ---
42 5.5 23 33 50 ---
41 5 26 37 53 ---
40 4.4 29 41 56 ---
39 3.9 33 45 60 ---
38 3.3 37 50 64 ---
37 2.7 41 55 68 ---
33-36 0.5-2.2 48 72 96 ---
1Average temperature during the wetting period in Fahrenheit or Celsius
2Required length of wetting to achieve 'low', 'medium', or a 'high' degree of
  infection
3Time in days until visible symptoms appear