Daily Observations at Hyslop Exp. Stn., Corvallis
May 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 | 84 | 42 | 0 | 87 | 53 | 78 | 55 | 2 | 0 | 13 | .195 |
| 2 | 80 | 45 | 0 | 86 | 57 | 78 | 59 | 2 | 0 | 13 | .135 |
| 3 | 79 | 43 | 0 | 90 | 56 | 83 | 58 | 4 | 0 | 11 | .131 |
| 4 | 77 | 49 | T | 90 | 57 | 82 | 60 | 2 | 0 | 13 | .140 |
| 5 | 65 | 47 | 0 | 79 | 59 | 74 | 62 | 9 | 0 | 6 | .172 |
| 6 | 64 | 38 | .01 | 79 | 54 | 74 | 58 | 14 | 0 | 1 | .153 |
| 7 | 70 | 45 | .31 | 85 | 54 | 76 | 56 | 7 | 0 | 8 | .158 |
| 8 | 65 | 44 | .18 | 76 | 58 | 71 | 59 | 10 | 0 | 5 | .079 |
| 9 | 65 | 40 | .09 | 74 | 55 | 69 | 57 | 12 | 0 | 3 | .070 |
| 10 | 66 | 36 | 0 | 77 | 52 | 70 | 56 | 14 | 0 | 1 | .144 |
| 11 | 62 | 44 | .06 | 66 | 51 | 64 | 54 | 12 | 0 | 3 | .105 |
| 12 | 63 | 43 | .01 | 75 | 54 | 67 | 54 | 12 | 0 | 3 | .056 |
| 13 | 65 | 36 | 0 | 74 | 51 | 68 | 56 | 14 | 0 | 1 | .118 |
| 14 | 72 | 45 | 0 | 82 | 51 | 75 | 53 | 6 | 0 | 9 | .166 |
| 15 | 68 | 47 | 0 | 82 | 60 | 75 | 60 | 7 | 0 | 8 | .250 |
| 16 | 64 | 49 | .01 | 73 | 58 | 68 | 59 | 8 | 0 | 7 | .017 |
| 17 | 67 | 44 | 0 | 84 | 57 | 76 | 54 | 9 | 0 | 6 | .173 |
| 18 | 72 | 49 | .22 | 62 | 57 | 81 | 59 | 4 | 0 | 11 | .221 |
| 19 | 63 | 50 | .06 | 71 | 60 | 66 | 61 | 8 | 0 | 7 | .004 |
| 20 | 66 | 43 | 0 | 79 | 54 | 71 | 59 | 10 | 0 | 5 | .109 |
| 21 | 73 | 50 | 0 | 86 | 56 | 77 | 57 | 3 | 0 | 12 | .213 |
| 22 | 65 | 50 | 0 | 74 | 60 | 69 | 62 | 7 | 0 | 8 | .123 |
| 23 | 66 | 48 | .03 | 79 | 58 | 70 | 59 | 8 | 0 | 7 | .155 |
| 24 | 68 | 43 | .12 | 88 | 56 | 77 | 58 | 9 | 0 | 6 | .164 |
| 25 | 75 | 49 | 0 | 85 | 57 | 78 | 57 | 3 | 0 | 12 | .359 |
| 26 | 78 | 55 | .05 | 91 | 59 | 83 | 61 | 0 | 2 | 17 | .295 |
| 27 | 68 | 51 | .04 | 72 | 62 | 69 | 64 | 5 | 0 | 10 | .108 |
| 28 | 65 | 48 | .05 | 70 | 58 | 66 | 59 | 8 | 0 | 7 | .059 |
| 29 | 63 | 48 | .03 | 83 | 58 | 72 | 58 | 9 | 0 | 6 | .200 |
| 30 | 61 | 50 | .01 | 67 | 59 | 64 | 58 | 9 | 0 | 6 | .08 |
| 31 | 66 | 48 | .02 | 72 | 58 | 68 | 58 | 8 | 0 | 7 | .13 |
| Average/Total | 68.5 | 45.8 | 1.30 | 78.6 | 56.4 | 72.9 | 58.1 | 235 | 2 | 232 | 4.482 |
| Departure | 2.4 | 2.7 | -0.65 |   |   |   |   |   |   |   |   |