Please Note

The GDD models have only been “ground-truthed” in the Great Lakes region. Use of models outside of this region, including the North East, Great Plains and Transition Zones, should be used with caution. We do not recommend the GDD models we use for the mid/southern transition zone and southern states.

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MSU Poa Seedhead Flush (GDD 22)
forecast for Mon, May. 25. 2026

 

Forecasted GDD Total: 2379 (Base 22) through Mon, May. 25, 2026

  

Swansea, MA

        

Forecast »

“Flashback” to 2025

5/15

5/16

5/17

5/18

5/19

5/20

5/21

5/22

5/23

5/24

5/25

5/26

5/27

Done

2900

Late

2450

Heavy

1500

Early

1050

No

0

 

Generously Supported By:



Tabular Data

Daily GDD accumulation for various base temperature models in 2025 & 2026

2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-15 17° 35° 4 0 0 0 0
02-16 24° 36° 13 0 0 0 0
02-17 23° 35° 19 0 0 0 0
02-18 30° 39° 32 3 0 0 0
02-19 26° 40° 43 4 0 0 0
02-20 25° 35° 51 4 0 0 0
02-21 29° 34° 60 4 0 0 0
02-22 23° 33° 66 4 0 0 0
02-23 25° 31° 73 4 0 0 0
02-24 16° 31° 74 4 0 0 0
02-25 8° 37° 74 4 0 0 0
02-26 24° 43° 86 5 0 0 0
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-27 19° 39° 92 5 0 0 0
02-28 18° 45° 102 5 0 0 0
03-01 17° 39° 108 5 0 0 0
03-02 7° 26° 108 5 0 0 0
03-03 0° 34° 108 5 0 0 0
03-04 29° 48° 124 11 0 0 0
03-05 25° 40° 134 12 0 0 0
03-06 33° 36° 147 14 0 0 0
03-07 33° 45° 164 22 0 0 0
03-08 43° 59° 193 40 9 1 0
03-09 36° 68° 223 60 19 3 0
03-10 41° 65° 253 81 29 5 0
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-11 39° 61° 282 99 38 6 0
03-12 32° 58° 305 112 41 6 0
03-13 29° 41° 318 115 41 6 0
03-14 33° 49° 337 124 41 6 0
03-15 28° 43° 350 128 41 6 0
03-16 36° 60° 377 144 47 6 0
03-17 30° 59° 400 157 50 6 0
03-18 22° 35° 406 157 50 6 0
03-19 22° 38° 414 157 50 6 0
03-20 30° 50° 432 165 50 6 0
03-21 41° 55° 459 182 57 6 0
03-22 34° 45° 477 190 57 6 0
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-23 34° 43° 494 196 57 6 0
03-24 31° 45° 510 202 57 6 0
03-25 30° 48° 527 210 57 6 0
03-26 40° 60° 555 227 65 6 0
03-27 31° 52° 574 237 65 6 0
03-28 28° 39° 586 238 65 6 0
03-29 25° 46° 599 242 65 6 0
03-30 38° 60° 626 259 72 6 0
03-31 47° 68° 662 284 87 13 3
04-01 45° 59° 692 305 98 16 3
04-02 37° 45° 712 314 98 16 3
04-03 37° 63° 740 333 106 16 3
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-04 39° 61° 768 351 114 16 3
04-05 40° 58° 795 368 121 16 3
04-06 36° 50° 816 379 122 16 3
04-07 33° 53° 837 389 123 16 3
04-08 28° 46° 852 395 123 16 3
04-09 25° 48° 867 400 123 16 3
04-10 32° 61° 891 414 127 16 3
04-11 45° 62° 923 435 139 20 3
04-12 34° 53° 944 447 140 20 3
04-13 43° 63° 975 468 152 23 3
04-14 51° 77° 1017 500 174 37 12
04-15 53° 80° 1062 535 198 54 23
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-16 55° 82° 1109 571 225 72 37
04-17 50° 69° 1147 599 243 82 42
04-18 46° 53° 1174 617 250 82 42
04-19 37° 52° 1197 629 253 82 42
04-20 32° 50° 1216 638 253 82 42
04-21 31° 49° 1234 646 253 82 42
04-22 34° 46° 1252 654 253 82 42
04-23 44° 67° 1285 678 266 88 42
04-24 36° 56° 1309 692 270 88 42
04-25 32° 55° 1330 703 272 88 42
04-26 42° 58° 1358 721 280 88 42
04-27 36° 65° 1387 740 288 88 42
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-28 38° 62° 1415 758 297 89 42
04-29 45° 62° 1447 780 308 92 42
04-30 46° 53° 1475 797 316 92 42
05-01 48° 64° 1509 821 330 98 43
05-02 45° 55° 1537 839 338 98 43
05-03 40° 55° 1562 855 343 98 43
05-04 39° 68° 1593 876 355 101 43
05-05 48° 71° 1631 903 372 111 48
05-06 57° 67° 1671 934 392 123 55
05-07 49° 65° 1706 959 408 130 57
05-08 40° 62° 1736 978 417 132 57
05-09 40° 61° 1764 997 426 132 57
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-10 53° 67° 1803 1025 444 143 62
05-11 44° 62° 1834 1046 455 146 62
05-12 42° 61° 1863 1066 465 147 62
05-13 45° 65° 1896 1089 478 152 62
05-14 51° 60° 1930 1113 492 158 63
05-15 47° 62° 1963 1135 504 163 63
05-16 43° 76° 2000 1163 521 172 68
05-17 58° 86° 2051 1203 552 195 85
05-18 60° 78° 2098 1240 579 214 99
05-19 64° 86° 2150 1283 612 238 119
05-20 64° 91° 2206 1329 647 266 142
05-21 54° 69° 2246 1358 667 278 148
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-22 44° 66° 2279 1381 680 283 148
05-23 42° 64° 2310 1403 691 286 148
05-24 46° 59° 2340 1423 702 288 148
05-25 50° 71° 2379 1452 720 299 154
05-26 52° 76° 2421 1484 742 313 163
05-27 54° 79° 2466 1519 767 330 175
05-28 53° 75° 2508 1551 789 344 184
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-15 18° 28° 1 0 0 0 0
02-16 25° 40° 12 0 0 0 0
02-17 21° 35° 17 0 0 0 0
02-18 16° 25° 17 0 0 0 0
02-19 17° 31° 19 0 0 0 0
02-20 14° 30° 19 0 0 0 0
02-21 20° 35° 25 0 0 0 0
02-22 16° 37° 29 0 0 0 0
02-23 25° 42° 41 2 0 0 0
02-24 25° 44° 54 5 0 0 0
02-25 36° 54° 76 18 3 0 0
02-26 35° 54° 99 30 5 0 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-27 36° 52° 121 42 7 0 0
02-28 34° 48° 139 50 7 0 0
03-01 26° 50° 155 56 7 0 0
03-02 18° 29° 157 56 7 0 0
03-03 12° 33° 158 56 7 0 0
03-04 21° 47° 169 58 7 0 0
03-05 40° 57° 196 75 14 0 0
03-06 36° 55° 219 88 17 0 0
03-07 29° 42° 233 92 17 0 0
03-08 30° 43° 247 96 17 0 0
03-09 26° 46° 262 100 17 0 0
03-10 29° 63° 286 114 21 0 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-11 30° 60° 308 127 24 0 0
03-12 37° 52° 331 139 26 0 0
03-13 34° 48° 350 149 26 0 0
03-14 38° 58° 376 165 32 0 0
03-15 36° 50° 397 175 33 0 0
03-16 44° 66° 430 199 46 5 0
03-17 45° 58° 460 219 56 7 0
03-18 36° 49° 481 229 57 7 0
03-19 31° 60° 504 243 60 7 0
03-20 40° 52° 528 257 64 7 0
03-21 39° 47° 550 268 66 7 0
03-22 32° 59° 573 282 69 7 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-23 29° 45° 589 287 69 7 0
03-24 29° 48° 606 294 69 7 0
03-25 37° 56° 630 309 74 7 0
03-26 36° 51° 652 321 76 7 0
03-27 30° 49° 669 328 76 7 0
03-28 32° 60° 693 342 80 7 0
03-29 36° 50° 714 353 81 7 0
03-30 36° 45° 733 362 81 7 0
03-31 42° 57° 761 379 88 7 0
04-01 39° 55° 786 395 94 7 0
04-02 29° 47° 802 401 94 7 0
04-03 38° 60° 829 418 101 7 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-04 52° 70° 868 447 119 18 6
04-05 40° 49° 890 459 122 18 6
04-06 40° 54° 916 475 127 18 6
04-07 38° 48° 937 486 128 18 6
04-08 30° 43° 952 490 128 18 6
04-09 27° 46° 966 495 128 18 6
04-10 29° 48° 983 502 128 18 6
04-11 35° 49° 1003 511 128 18 6
04-12 34° 38° 1017 516 128 18 6
04-13 37° 45° 1036 525 128 18 6
04-14 37° 67° 1066 545 138 20 6
04-15 47° 60° 1098 567 150 24 6
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-16 39° 51° 1121 580 153 24 6
04-17 36° 61° 1147 596 159 24 6
04-18 34° 64° 1174 613 166 24 6
04-19 53° 73° 1215 644 187 37 14
04-20 49° 67° 1251 669 203 44 17
04-21 36° 57° 1275 684 207 44 17
04-22 48° 70° 1312 711 224 54 21
04-23 47° 68° 1348 737 240 62 24
04-24 44° 68° 1382 761 254 67 25
04-25 51° 76° 1423 792 275 81 33
04-26 57° 60° 1460 819 292 89 37
04-27 44° 57° 1489 837 301 90 37
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-28 43° 74° 1525 864 317 98 40
04-29 47° 74° 1563 892 335 108 46
04-30 57° 74° 1607 926 359 124 56
05-01 42° 63° 1638 947 370 127 56
05-02 49° 72° 1676 975 388 137 62
05-03 56° 74° 1719 1008 411 153 72
05-04 58° 76° 1764 1043 436 170 84
05-05 55° 61° 1801 1069 453 178 87
05-06 56° 66° 1840 1098 472 189 93
05-07 55° 70° 1880 1129 492 202 101
05-08 52° 74° 1921 1160 513 214 108
05-09 52° 63° 1956 1185 528 222 111
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-10 49° 66° 1992 1210 544 229 113
05-11 47° 73° 2030 1238 562 239 118
05-12 39° 69° 2061 1260 573 243 118
05-13 51° 72° 2101 1290 593 254 125
05-14 50° 76° 2142 1321 614 267 133
05-15 61° 67° 2184 1352 636 281 141
05-16 61° 71° 2228 1387 660 297 152
05-17 59° 72° 2271 1420 683 312 163
05-18 57° 71° 2313 1452 705 326 172
05-19 50° 65° 2349 1477 721 334 174
05-20 48° 58° 2379 1498 731 337 174
05-21 47° 50° 2406 1515 738 337 174
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-22 45° 47° 2430 1528 742 337 174
05-23 44° 57° 2458 1547 750 337 174
05-24 46° 61° 2489 1568 761 340 174
05-25 48° 62° 2522 1591 774 345 174
05-26 44° 68° 2556 1615 788 351 175
05-27 47° 76° 2596 1644 808 363 182
05-28 53° 74° 2638 1676 830 377 191
05-29 55° 64° 2675 1704 847 386 195
05-30 58° 70° 2717 1735 869 400 204
05-31 52° 67° 2754 1763 886 409 208
06-01 48° 63° 2788 1787 900 415 209
06-02 49° 69° 2825 1814 917 424 213
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-03 49° 77° 2866 1845 938 437 221
06-04 54° 81° 2912 1880 964 455 234
06-05 57° 88° 2962 1921 994 477 251
06-06 66° 83° 3015 1964 1027 502 271
06-07 64° 72° 3061 1999 1053 520 284
06-08 58° 71° 3103 2032 1075 534 293
06-09 57° 67° 3143 2062 1095 546 300
06-10 59° 65° 3183 2092 1115 558 307
06-11 58° 80° 3230 2129 1142 577 321
06-12 62° 87° 3282 2171 1174 601 340
06-13 59° 76° 3328 2206 1200 619 353
06-14 55° 62° 3364 2233 1216 627 356
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-15 55° 70° 3405 2264 1237 640 364
06-16 54° 74° 3447 2296 1259 654 373
06-17 61° 70° 3491 2330 1283 670 384
06-18 63° 74° 3538 2366 1310 689 398
06-19 66° 87° 3592 2411 1344 715 419
06-20 68° 83° 3646 2455 1378 741 440
06-21 60° 85° 3696 2495 1408 763 457
06-22 68° 92° 3754 2543 1446 793 482
06-23 72° 89° 3813 2592 1485 824 508
06-24 72° 99° 3877 2645 1529 860 539
06-25 77° 94° 3940 2699 1572 895 569
06-26 61° 75° 3986 2735 1598 913 582
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-27 60° 74° 4031 2770 1623 930 594
06-28 60° 75° 4077 2806 1649 948 607
06-29 69° 88° 4133 2852 1685 976 630
06-30 64° 85° 4185 2894 1717 1000 649
07-01 70° 88° 4242 2941 1754 1029 673
07-02 72° 84° 4298 2987 1790 1057 696
07-03 66° 89° 4354 3033 1826 1085 719
07-04 60° 80° 4402 3071 1854 1105 734
07-05 57° 82° 4449 3108 1881 1124 748
07-06 67° 89° 4505 3154 1917 1152 771
07-07 70° 83° 4560 3199 1952 1179 793
07-08 74° 91° 4620 3249 1992 1211 820
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
07-09 71° 78° 4673 3291 2025 1236 840
07-10 65° 71° 4718 3327 2050 1253 852
07-11 64° 77° 4767 3366 2079 1274 868
07-12 67° 79° 4818 3407 2110 1297 886
07-13 65° 81° 4869 3448 2141 1320 904
07-14 66° 78° 4919 3488 2171 1342 921
07-15 73° 86° 4977 3535 2209 1372 946
07-16 71° 90° 5035 3584 2247 1402 971
07-17 77° 87° 5095 3634 2287 1434 998
07-18 66° 81° 5146 3675 2318 1457 1016
07-19 56° 82° 5194 3713 2346 1477 1031
07-20 70° 81° 5247 3756 2379 1502 1051
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
07-21 63° 80° 5297 3796 2409 1524 1068
07-22 53° 78° 5341 3830 2433 1540 1079
07-23 56° 81° 5387 3866 2459 1558 1092
07-24 64° 86° 5440 3909 2492 1583 1112
07-25 70° 94° 5500 3959 2532 1615 1139
07-26 66° 80° 5551 4000 2563 1638 1157
07-27 61° 75° 5597 4036 2589 1656 1170
07-28 69° 88° 5654 4083 2626 1685 1194
07-29 71° 96° 5716 4134 2668 1719 1223
07-30 73° 92° 5776 4185 2708 1751 1250
07-31 63° 81° 5826 4225 2738 1773 1267
08-01 58° 73° 5870 4258 2762 1789 1278
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-02 51° 78° 5912 4291 2784 1803 1287
08-03 54° 81° 5958 4327 2810 1821 1300
08-04 57° 85° 6007 4366 2839 1842 1316
08-05 63° 80° 6056 4405 2868 1863 1332
08-06 59° 79° 6104 4443 2896 1883 1347
08-07 61° 81° 6153 4481 2925 1904 1363
08-08 53° 81° 6197 4516 2949 1920 1374
08-09 51° 81° 6241 4550 2973 1936 1385
08-10 59° 84° 6291 4590 3003 1958 1402
08-11 62° 90° 6345 4633 3037 1984 1423
08-12 67° 88° 6400 4679 3072 2011 1445
08-13 69° 84° 6454 4723 3106 2037 1466
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-14 72° 86° 6511 4770 3143 2066 1490
08-15 65° 82° 6563 4811 3175 2090 1509
08-16 58° 81° 6611 4849 3203 2110 1524
08-17 66° 87° 6665 4894 3237 2136 1545
08-18 56° 72° 6707 4926 3259 2150 1554
08-19 49° 74° 6747 4956 3279 2162 1561
08-20 55° 69° 6787 4986 3299 2174 1568
08-21 56° 67° 6827 5015 3319 2186 1575
08-22 56° 82° 6873 5052 3345 2204 1588
08-23 59° 83° 6922 5091 3374 2225 1604
08-24 60° 78° 6969 5128 3401 2244 1618
08-25 65° 82° 7021 5170 3433 2268 1637
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-26 59° 78° 7068 5207 3460 2287 1651
08-27 53° 76° 7110 5239 3482 2301 1660
08-28 49° 77° 7151 5270 3503 2314 1668
08-29 60° 71° 7195 5303 3527 2330 1679
08-30 53° 74° 7236 5335 3548 2343 1687
08-31 51° 76° 7277 5366 3569 2356 1695
09-01 51° 75° 7318 5397 3590 2369 1703
09-02 56° 77° 7363 5432 3615 2386 1715
09-03 51° 75° 7404 5463 3636 2399 1723
09-04 51° 75° 7445 5494 3657 2412 1731
09-05 65° 79° 7495 5534 3687 2434 1748
09-06 68° 81° 7547 5576 3719 2458 1767
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
09-07 60° 69° 7590 5609 3742 2473 1777
09-08 51° 68° 7628 5636 3760 2483 1782
09-09 47° 72° 7665 5664 3777 2492 1786
09-10 54° 68° 7704 5693 3796 2503 1792
09-11 51° 76° 7746 5725 3818 2517 1801
09-12 55° 73° 7788 5757 3840 2531 1810
09-13 48° 72° 7826 5785 3858 2541 1815
09-14 55° 77° 7870 5819 3882 2557 1826
09-15 57° 77° 7915 5854 3907 2574 1838
09-16 56° 73° 7957 5886 3929 2588 1847
09-17 53° 74° 7999 5918 3951 2602 1856
09-18 62° 74° 8045 5954 3977 2620 1869
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
09-19 57° 81° 8092 5991 4004 2639 1883
09-20 50° 70° 8130 6019 4022 2649 1888
09-21 42° 69° 8164 6043 4036 2655 1889
09-22 48° 72° 8202 6070 4054 2665 1894
09-23 56° 78° 8246 6105 4078 2681 1905
09-24 64° 67° 8290 6138 4102 2697 1916
09-25 63° 72° 8335 6174 4127 2714 1928
09-26 65° 80° 8386 6214 4158 2737 1946
09-27 57° 77° 8431 6249 4183 2754 1958
09-28 62° 79° 8479 6288 4211 2774 1973
09-29 57° 77° 8524 6323 4236 2791 1985
09-30 54° 74° 8566 6355 4258 2805 1994
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55

 

Latest Updates

February 16th, 2026Welcome to the 2026 GDD Tracking Season

Although Punxsutawney Phil saw his shadow predicting six more weeks of winter, GDDTracker will start counting on February 15. Spring is when GDDTracker receives the most attention for alerting turfgrass managers of optimal application timing windows for suppressing annual bluegrass seedheads and crabgrass preemergence applications. As spring turns to summer, there are several models that may be helpful throughout the season including the early season dollar spot DMI timer and the Smith-Kerns dollar spot prediction model. To learn about all the available models, click on the "About" tab at the top of the screen. Thanks for your continued support and use of GDDTracker and best wishes for a successful 2026!


 

March 18th, 2024Timing crabgrass preemergence applications in spring

Don't miss this update from from Kevin Frank regarding timing of crabgrass preemergence herbicides.


 

 

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