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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Ester/Amine Spring Broadleaf Herbicide Timer - Purdue (GDD 50)
forecast for Sat, Apr. 4. 2026

 

Forecasted GDD Total: 115 (Base 50) through Sat, Apr. 4, 2026

  

Ankeny, IA

        

Forecast »

“Flashback” to 2025

3/27

3/28

3/29

3/30

3/31

4/1

4/2

4/3

4/4

4/5

4/6

4/7

4/8

Over

601

Amine

201

Ester or Amine

151

Ester

110

Early

71

Under

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 36° 63° 28 18 8 0 0
02-16 41° 68° 61 41 21 5 0
02-17 40° 64° 91 61 31 7 0
02-18 43° 61° 120 80 40 9 0
02-19 25° 37° 130 80 40 9 0
02-20 13° 25° 130 80 40 9 0
02-21 11° 22° 130 80 40 9 0
02-22 7° 22° 130 80 40 9 0
02-23 0° 19° 130 80 40 9 0
02-24 16° 39° 135 80 40 9 0
02-25 24° 35° 142 80 40 9 0
02-26 23° 50° 157 85 40 9 0
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-27 33° 64° 183 102 47 9 0
02-28 24° 38° 192 102 47 9 0
03-01 18° 32° 196 102 47 9 0
03-02 29° 45° 211 107 47 9 0
03-03 37° 42° 228 114 47 9 0
03-04 37° 49° 249 125 48 9 0
03-05 41° 57° 276 142 55 9 0
03-06 45° 69° 312 168 71 16 2
03-07 32° 53° 332 178 71 16 2
03-08 34° 69° 362 198 81 18 2
03-09 47° 72° 400 226 99 28 7
03-10 39° 62° 428 244 107 28 7
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-11 31° 47° 446 252 107 28 7
03-12 26° 54° 464 260 107 28 7
03-13 33° 53° 484 271 108 28 7
03-14 32° 50° 504 280 108 28 7
03-15 20° 41° 512 280 108 28 7
03-16 5° 20° 512 280 108 28 7
03-17 6° 25° 512 280 108 28 7
03-18 23° 62° 533 290 109 28 7
03-19 36° 74° 566 314 122 33 8
03-20 51° 79° 609 347 145 48 17
03-21 52° 90° 657 385 174 69 33
03-22 36° 73° 690 408 186 73 33
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-23 28° 51° 708 415 186 73 33
03-24 35° 59° 732 430 191 73 33
03-25 41° 79° 770 458 209 83 38
03-26 44° 68° 804 482 223 89 39
03-27 30° 49° 822 490 223 89 39
03-28 19° 59° 839 497 223 89 39
03-29 37° 68° 869 517 233 92 39
03-30 45° 89° 914 552 258 109 51
03-31 45° 68° 949 576 272 115 52
04-01 40° 49° 971 589 275 115 52
04-02 39° 54° 996 603 279 115 52
04-03 37° 62° 1023 621 287 115 52
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-04 36° 47° 1043 630 287 115 52
04-05 31° 56° 1064 642 288 115 52
04-06 34° 51° 1085 653 289 115 52
04-07 26° 49° 1100 658 289 115 52
04-08 39° 69° 1132 680 301 119 52
04-09 46° 63° 1165 703 314 123 52
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-15 18° 27° 0 0 0 0 0
02-16 4° 16° 0 0 0 0 0
02-17 -4° 5° 0 0 0 0 0
02-18 -13° 3° 0 0 0 0 0
02-19 -5° 8° 0 0 0 0 0
02-20 -8° 13° 0 0 0 0 0
02-21 4° 21° 0 0 0 0 0
02-22 14° 38° 4 0 0 0 0
02-23 23° 62° 25 11 1 0 0
02-24 41° 59° 52 28 8 0 0
02-25 31° 60° 76 42 12 0 0
02-26 38° 53° 100 56 16 0 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-27 36° 54° 123 69 19 0 0
02-28 33° 58° 146 82 22 0 0
03-01 21° 31° 150 82 22 0 0
03-02 16° 47° 159 82 22 0 0
03-03 32° 64° 185 98 28 0 0
03-04 42° 56° 212 115 35 0 0
03-05 27° 37° 222 115 35 0 0
03-06 22° 43° 233 116 35 0 0
03-07 31° 37° 245 118 35 0 0
03-08 26° 50° 261 123 35 0 0
03-09 31° 62° 285 138 39 0 0
03-10 35° 78° 319 162 54 7 2
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-11 36° 57° 344 177 58 7 2
03-12 31° 68° 372 195 66 7 2
03-13 38° 76° 407 220 81 14 4
03-14 54° 80° 452 255 106 31 16
03-15 32° 53° 472 265 107 31 16
03-16 25° 46° 486 269 107 31 16
03-17 32° 77° 518 291 119 35 16
03-18 45° 76° 556 319 137 45 21
03-19 33° 56° 579 332 140 45 21
03-20 28° 48° 595 338 140 45 21
03-21 37° 58° 621 354 146 45 21
03-22 26° 60° 642 365 147 45 21
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-23 38° 53° 666 379 150 45 21
03-24 30° 53° 685 388 150 45 21
03-25 39° 57° 711 404 157 45 21
03-26 31° 62° 736 419 161 45 21
03-27 43° 69° 770 443 175 51 22
03-28 50° 81° 814 477 199 67 33
03-29 55° 76° 857 510 223 83 43
03-30 34° 61° 883 526 229 83 43
03-31 31° 49° 901 534 229 83 43
04-01 32° 46° 918 541 229 83 43
04-02 45° 69° 953 566 244 90 45
04-03 37° 52° 976 579 247 90 45
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-04 35° 49° 996 589 247 90 45
04-05 36° 48° 1016 599 247 90 45
04-06 26° 56° 1035 608 247 90 45
04-07 32° 45° 1052 615 247 90 45
04-08 26° 54° 1070 623 247 90 45
04-09 38° 65° 1099 642 256 91 45
04-10 42° 61° 1129 661 265 92 45
04-11 44° 56° 1156 679 273 92 45
04-12 36° 71° 1188 701 285 96 45
04-13 53° 78° 1231 734 308 111 56
04-14 46° 64° 1264 757 321 116 56
04-15 37° 63° 1292 775 329 116 56
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-16 37° 75° 1326 799 343 122 57
04-17 57° 77° 1371 834 368 140 69
04-18 51° 68° 1409 862 385 149 73
04-19 39° 57° 1435 878 392 149 73
04-20 42° 51° 1459 892 396 149 73
04-21 44° 65° 1492 915 409 154 73
04-22 52° 70° 1531 944 427 165 79
04-23 56° 77° 1575 978 452 181 91
04-24 56° 71° 1617 1010 474 195 99
04-25 51° 61° 1651 1034 488 201 100
04-26 41° 64° 1681 1054 498 203 100
04-27 46° 66° 1715 1078 512 209 101
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-28 57° 81° 1763 1115 539 228 116
04-29 48° 71° 1800 1143 557 238 120
04-30 45° 67° 1834 1167 571 244 121
05-01 53° 65° 1871 1194 588 253 125
05-02 45° 56° 1900 1213 596 254 125
05-03 45° 62° 1931 1234 608 257 125
05-04 40° 72° 1965 1258 622 263 126
05-05 46° 73° 2003 1286 640 273 131
05-06 47° 76° 2042 1315 659 284 138
05-07 54° 80° 2087 1350 684 301 149
05-08 51° 74° 2128 1381 704 314 157
05-09 46° 76° 2167 1410 723 325 163
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-10 52° 86° 2214 1447 751 344 177
05-11 55° 83° 2261 1484 778 363 191
05-12 49° 84° 2305 1518 802 379 202
05-13 58° 83° 2354 1557 830 400 218
05-14 60° 85° 2404 1597 861 422 236
05-15 65° 80° 2455 1638 892 445 253
05-16 54° 74° 2497 1670 914 459 262
05-17 48° 66° 2532 1695 929 466 264
05-18 39° 74° 2566 1719 943 472 266
05-19 51° 65° 2602 1745 959 480 269
05-20 50° 63° 2637 1770 974 487 271
05-21 48° 57° 2668 1791 985 490 271
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-22 43° 61° 2698 1811 995 492 271
05-23 43° 67° 2731 1834 1008 497 271
05-24 53° 67° 2769 1862 1026 507 276
05-25 54° 68° 2809 1892 1046 519 282
05-26 48° 70° 2846 1919 1062 528 286
05-27 55° 64° 2883 1946 1080 537 291
05-28 55° 66° 2921 1974 1098 547 296
05-29 52° 69° 2960 2003 1116 558 301
05-30 53° 79° 3004 2037 1141 574 312
05-31 54° 84° 3051 2074 1168 593 326
06-01 58° 80° 3098 2111 1195 612 341
06-02 58° 88° 3149 2152 1226 635 359
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-03 57° 77° 3194 2187 1251 652 371
06-04 52° 76° 3236 2219 1273 666 379
06-05 55° 78° 3280 2253 1297 682 391
06-06 62° 79° 3329 2292 1326 703 406
06-07 65° 72° 3375 2328 1352 721 419
06-08 59° 70° 3418 2360 1374 735 429
06-09 55° 69° 3458 2391 1395 748 436
06-10 50° 84° 3503 2426 1420 765 449
06-11 61° 94° 3559 2472 1456 793 471
06-12 66° 86° 3612 2515 1489 818 492
06-13 64° 84° 3664 2557 1521 842 511
06-14 66° 88° 3719 2602 1556 869 533
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-15 66° 83° 3772 2645 1589 894 552
06-16 67° 88° 3828 2690 1624 921 575
06-17 64° 80° 3878 2731 1654 944 592
06-18 64° 77° 3926 2769 1683 964 608
06-19 60° 85° 3977 2810 1714 987 626
06-20 68° 89° 4034 2857 1751 1016 649
06-21 79° 95° 4099 2912 1796 1053 682
06-22 77° 93° 4162 2965 1839 1088 712
06-23 73° 91° 4222 3015 1879 1120 739
06-24 69° 78° 4274 3057 1911 1144 758
06-25 70° 88° 4331 3104 1948 1173 782
06-26 70° 88° 4388 3151 1985 1202 806
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-27 64° 83° 4440 3193 2017 1226 824
06-28 69° 90° 4497 3240 2054 1255 849
06-29 71° 81° 4551 3284 2088 1281 870
06-30 68° 83° 4605 3328 2122 1307 890
07-01 64° 84° 4657 3370 2154 1331 909
07-02 64° 84° 4709 3412 2185 1355 928
07-03 68° 91° 4766 3459 2223 1384 953
07-04 73° 89° 4825 3508 2262 1415 979
07-05 71° 83° 4881 3554 2297 1443 1001
07-06 69° 86° 4936 3599 2333 1470 1024
07-07 66° 86° 4990 3643 2367 1496 1045
07-08 67° 83° 5043 3686 2400 1521 1065
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
07-09 67° 87° 5098 3731 2435 1548 1087
07-10 70° 87° 5154 3777 2471 1576 1110
07-11 68° 77° 5205 3818 2502 1599 1127
07-12 65° 79° 5255 3858 2532 1621 1144
07-13 61° 81° 5304 3897 2560 1642 1160
07-14 64° 87° 5357 3940 2594 1667 1180
07-15 67° 87° 5412 3985 2629 1694 1203
07-16 71° 81° 5466 4029 2663 1720 1224
07-17 60° 72° 5511 4064 2688 1737 1235
07-18 59° 81° 5559 4102 2716 1757 1250
07-19 68° 86° 5614 4146 2750 1783 1272
07-20 71° 85° 5669 4192 2786 1811 1295
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
07-21 73° 82° 5725 4238 2822 1839 1318
07-22 71° 88° 5783 4286 2860 1869 1342
07-23 74° 91° 5843 4336 2900 1901 1370
07-24 70° 82° 5897 4380 2934 1927 1390
07-25 69° 84° 5951 4424 2968 1953 1412
07-26 72° 86° 6008 4471 3005 1982 1436
07-27 73° 91° 6068 4521 3045 2014 1462
07-28 68° 88° 6124 4567 3081 2042 1485
07-29 69° 91° 6182 4615 3118 2072 1510
07-30 68° 80° 6234 4656 3150 2095 1529
07-31 63° 76° 6281 4694 3178 2115 1544
08-01 57° 74° 6325 4728 3202 2131 1555
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-02 58° 77° 6371 4764 3228 2149 1567
08-03 57° 76° 6415 4798 3252 2165 1579
08-04 61° 77° 6462 4835 3279 2184 1593
08-05 60° 81° 6511 4874 3308 2205 1608
08-06 66° 81° 6562 4915 3339 2228 1627
08-07 70° 83° 6617 4960 3374 2255 1649
08-08 72° 89° 6676 5009 3413 2286 1674
08-09 74° 82° 6732 5055 3449 2314 1697
08-10 71° 82° 6787 5100 3483 2341 1719
08-11 66° 80° 6838 5141 3515 2364 1737
08-12 68° 83° 6891 5184 3548 2389 1758
08-13 62° 81° 6941 5224 3578 2411 1774
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-14 63° 83° 6992 5265 3609 2434 1793
08-15 68° 90° 7049 5312 3646 2463 1816
08-16 73° 93° 7110 5363 3687 2496 1844
08-17 73° 93° 7171 5414 3728 2529 1873
08-18 72° 86° 7228 5461 3765 2558 1896
08-19 70° 87° 7284 5507 3801 2586 1920
08-20 69° 86° 7340 5553 3836 2614 1942
08-21 66° 81° 7391 5594 3868 2637 1960
08-22 61° 82° 7441 5633 3897 2658 1977
08-23 63° 73° 7486 5669 3923 2676 1990
08-24 54° 73° 7528 5701 3945 2690 1998
08-25 49° 71° 7566 5729 3963 2700 2004
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-26 47° 75° 7605 5758 3982 2711 2010
08-27 57° 80° 7652 5795 4009 2730 2023
08-28 57° 82° 7699 5832 4036 2749 2038
08-29 59° 83° 7748 5871 4065 2770 2054
08-30 62° 82° 7799 5912 4095 2793 2071
08-31 65° 77° 7848 5951 4125 2814 2087
09-01 60° 77° 7894 5987 4151 2832 2101
09-02 54° 80° 7939 6022 4176 2849 2113
09-03 55° 70° 7980 6052 4196 2861 2120
09-04 44° 72° 8016 6079 4212 2870 2123
09-05 52° 66° 8052 6105 4229 2878 2127
09-06 44° 66° 8085 6128 4242 2883 2127
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
09-07 42° 73° 8121 6154 4257 2891 2129
09-08 50° 80° 8163 6186 4280 2905 2139
09-09 56° 77° 8208 6221 4305 2922 2151
09-10 58° 84° 8257 6260 4334 2943 2166
09-11 58° 86° 8307 6300 4364 2965 2184
09-12 63° 85° 8360 6343 4396 2990 2203
09-13 67° 98° 8420 6393 4437 3022 2231
09-14 66° 91° 8476 6439 4473 3050 2254
09-15 71° 91° 8535 6488 4512 3081 2280
09-16 67° 88° 8591 6534 4548 3109 2302
09-17 65° 80° 8641 6574 4578 3131 2320
09-18 62° 74° 8687 6610 4604 3149 2333
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
09-19 64° 78° 8737 6650 4634 3171 2349
09-20 59° 74° 8781 6684 4658 3187 2361
09-21 58° 79° 8828 6721 4685 3206 2374
09-22 64° 85° 8880 6763 4717 3230 2394
09-23 60° 75° 8926 6799 4743 3248 2407
09-24 58° 79° 8973 6835 4769 3266 2420
09-25 52° 81° 9017 6870 4794 3283 2432
09-26 55° 87° 9066 6909 4823 3304 2448
09-27 57° 85° 9115 6948 4852 3325 2463
09-28 53° 85° 9162 6984 4878 3343 2477
09-29 60° 87° 9213 7026 4910 3367 2496
09-30 56° 85° 9262 7065 4939 3388 2512
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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