Daily Observations at Hyslop Exp. Stn., Corvallis
April 2004
Bold = new daily record set (old record, year)
| Day | Max Temp (F) | Min Temp (F) | Precip (in) | 2 in soil Max | 2 in soil Min | 4 in soil Max | 4 in soil Min | Heating Deg. Days | Cooling Deg. Days | Growing Deg. Days | Evaporation (in.) |
| 1 | 55 | 30 | .01 | 66 | 43 | 59 | 46 | 22 | 0 | 0 | .080 |
| 2 | 58 | 37 | 0 | 67 | 43 | 59 | 45 | 17 | 0 | 0 | .158 |
| 3 | 70 | 40 | 0 | 67 | 45 | 61 | 44 | 10 | 0 | 5 | .249 |
| 4 | 75 | 35 | 0 | 75 | 36 | 66 | 49 | 10 | 0 | 5 | .272 |
| 5 | 63 | 39 | 0 | 69 | 46 | 65 | 48 | 14 | 0 | 1 | .017 |
| 6 | 57 | 45 | 0 | 64 | 50 | 58 | 51 | 14 | 0 | 1 | .081 |
| 7 | 61 | 41 | 0 | 64 | 51 | 61 | 53 | 14 | 0 | 1 | .041 |
| 8 | 62 | 42 | 0 | 69 | 49 | 63 | 52 | 13 | 0 | 2 | .120 |
| 9 | 67 | 39 | 0 | 74 | 49 | 67 | 50 | 12 | 0 | 3 | .161 |
| 10 | 73 | 45 | 0 | 76 | 49 | 69 | 51 | 6 | 0 | 9 | .255 |
| 11 | 80 | 43 | 0 | 80 | 53 | 74 | 54 | 3 | 0 | 12 | .271 |
| 12 | 80 | 38 | 0 | 84 | 53 | 76 | 54 | 6 | 0 | 9 | .172 |
| 13 | 65 | 33 | 0 | 71 | 47 | 64 | 52 | 16 | 0 | 0 | .079 |
| 14 | 62 | 40 | .54 | 68 | 47 | 63 | 51 | 14 | 0 | 1 | .156 |
| 15 | 55 | 40 | .37 | 62 | 49 | 58 | 52 | 17 | 0 | 0 | .059 |
| 16 | 55 | 39 | .06 | 61 | 49 | 57 | 49 | 18 | 0 | 0 | .104 |
| 17 | 58 | 44 | .01 | 68 | 48 | 62 | 49 | 14 | 0 | 1 | .128 |
| 18 | 58 | 36 | T | 70 | 49 | 64 | 53 | 18 | 0 | 0 | .105 |
| 19 | 57 | 37 | .17 | 63 | 49 | 59 | 49 | 18 | 0 | 0 | .069 |
| 20 | 55 | 42 | .50 | 58 | 49 | 56 | 50 | 16 | 0 | 0 | .011 |
| 21 | 50 | 44 | .52 | 55 | 50 | 54 | 51 | 18 | 0 | 0 | .013 |
| 22 | 58 | 34 | .01 | 65 | 48 | 59 | 50 | 19 | 0 | 0 | .091 |
| 23 | 66 | 39 | 0 | 74 | 48 | 67 | 49 | 12 | 0 | 3 | .103 |
| 24 | 61 | 35 | .14 | 66 | 47 | 60 | 50 | 17 | 0 | 0 | .102 |
| 25 | 63 | 40 | T | 70 | 47 | 64 | 48 | 13 | 0 | 2 | .210 |
| 26 | 76 | 42 | 0 | 75 | 49 | 69 | 51 | 6 | 0 | 9 | .204 |
| 27 | 83 | 44 | 0 | 81 | 52 | 73 | 55 | 1 | 0 | 14 | .205 |
| 28 | 75 | 38 | 0 | 79 | 52 | 71 | 55 | 8 | 0 | 7 | .267 |
| 29 | 65 | 38 | 0 | 76 | 51 | 70 | 53 | 13 | 0 | 2 | .196 |
| 30 | 75 | 40 | 0 | 78 | 50 | 72 | 53 | 7 | 0 | 8 | .247 |
| Average/Total | 64.6 | 39.3 | 2.33 | 69.8 | 48.3 | 64.0 | 50.6 | 386 | 0 | 95 | 4.226 |
| Departure | 5.1 | 0.1 | -0.23 |   |   |   |   |   |   |   |   |