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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Crabgrass/Annual Bluegrass Preemergence Timer (GDD 32)
through Fri, Apr. 3. 2026

 

GDD Total: 604 (Base 32) through Fri, Apr. 3, 2026

  

Coralville, IA

        

Forecast »

“Flashback” to 2025

3/28

3/29

3/30

3/31

4/1

4/2

4/3

4/4

4/5

4/6

4/7

4/8

4/9

Done

801

Late

500

Optimum

250

Early

171

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 27° 62° 23 13 3 0 0
02-16 34° 69° 52 32 12 2 0
02-17 37° 59° 79 49 19 2 0
02-18 41° 62° 109 69 29 3 0
02-19 26° 47° 123 73 29 3 0
02-20 19° 38° 130 73 29 3 0
02-21 15° 25° 130 73 29 3 0
02-22 8° 18° 130 73 29 3 0
02-23 8° 25° 130 73 29 3 0
02-24 14° 46° 138 73 29 3 0
02-25 23° 32° 144 73 29 3 0
02-26 25° 50° 159 79 29 3 0
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-27 26° 68° 184 93 34 3 0
02-28 23° 40° 194 93 34 3 0
03-01 17° 34° 197 93 34 3 0
03-02 26° 41° 209 95 34 3 0
03-03 37° 46° 228 104 34 3 0
03-04 34° 46° 246 112 34 3 0
03-05 41° 57° 273 129 40 3 0
03-06 48° 69° 309 155 57 12 4
03-07 31° 63° 334 171 62 12 4
03-08 30° 68° 362 188 69 12 4
03-09 46° 75° 400 216 88 22 9
03-10 42° 54° 426 232 94 22 9
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-11 33° 45° 443 239 94 22 9
03-12 25° 46° 457 243 94 22 9
03-13 35° 51° 478 254 95 22 9
03-14 33° 48° 496 262 95 22 9
03-15 30° 47° 512 269 95 22 9
03-16 10° 29° 512 269 95 22 9
03-17 5° 23° 512 269 95 22 9
03-18 22° 51° 527 273 95 22 9
03-19 33° 71° 557 293 105 24 9
03-20 46° 77° 596 323 124 36 15
03-21 48° 86° 641 357 149 52 27
03-22 40° 69° 674 380 161 57 27
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-23 26° 49° 689 386 161 57 27
03-24 36° 57° 714 400 166 57 27
03-25 42° 75° 751 427 183 66 31
03-26 48° 73° 790 456 201 76 37
03-27 31° 48° 807 464 201 76 37
03-28 19° 54° 822 469 201 76 37
03-29 41° 63° 852 488 211 78 37
03-30 45° 85° 895 522 235 94 47
03-31 55° 73° 937 553 256 107 56
04-01 38° 53° 961 567 260 107 56
04-02 38° 71° 994 590 273 112 56
04-03 40° 52° 1017 604 277 112 56
2026Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-04 40° 48° 1039 616 279 112 56
04-05 33° 54° 1061 627 280 112 56
04-06 33° 49° 1080 636 280 112 56
04-07 26° 46° 1094 641 280 112 56
04-08 38° 68° 1126 662 291 115 56
04-09 46° 63° 1158 684 304 120 56
04-10 45° 61° 1189 706 315 123 56
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-15 22° 28° 3 0 0 0 0
02-16 2° 23° 3 0 0 0 0
02-17 -6° 4° 3 0 0 0 0
02-18 -15° 5° 3 0 0 0 0
02-19 -2° 8° 3 0 0 0 0
02-20 -5° 16° 3 0 0 0 0
02-21 -7° 22° 3 0 0 0 0
02-22 6° 34° 3 0 0 0 0
02-23 22° 50° 17 4 0 0 0
02-24 38° 57° 43 19 6 0 0
02-25 34° 55° 65 32 8 0 0
02-26 36° 53° 88 44 10 0 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
02-27 32° 53° 108 55 11 0 0
02-28 33° 59° 132 69 15 0 0
03-01 21° 33° 137 69 15 0 0
03-02 14° 40° 143 69 15 0 0
03-03 30° 56° 164 80 17 0 0
03-04 45° 53° 191 98 24 0 0
03-05 28° 45° 205 102 24 0 0
03-06 22° 42° 215 102 24 0 0
03-07 31° 38° 228 105 24 0 0
03-08 26° 50° 244 110 24 0 0
03-09 29° 63° 267 124 27 0 0
03-10 33° 74° 299 146 39 4 0
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-11 41° 59° 327 164 47 4 0
03-12 28° 65° 352 178 52 4 0
03-13 35° 72° 384 200 64 8 0
03-14 54° 81° 429 236 89 25 13
03-15 32° 54° 450 247 90 25 13
03-16 28° 44° 464 251 90 25 13
03-17 24° 69° 489 266 95 25 13
03-18 38° 73° 523 289 109 31 13
03-19 35° 53° 545 301 111 31 13
03-20 29° 45° 560 306 111 31 13
03-21 31° 61° 584 320 115 31 13
03-22 26° 53° 601 328 115 31 13
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
03-23 37° 49° 622 339 115 31 13
03-24 30° 53° 641 348 115 31 13
03-25 41° 55° 667 364 121 31 13
03-26 31° 58° 690 377 124 31 13
03-27 41° 64° 721 397 135 34 13
03-28 49° 80° 763 430 157 48 23
03-29 59° 76° 808 465 182 65 35
03-30 39° 63° 838 484 192 67 35
03-31 33° 51° 858 495 192 67 35
04-01 32° 47° 876 502 192 67 35
04-02 44° 71° 911 527 207 74 37
04-03 39° 51° 934 540 210 74 37
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-04 35° 49° 953 550 210 74 37
04-05 36° 47° 973 560 210 74 37
04-06 29° 54° 992 569 210 74 37
04-07 34° 45° 1010 576 210 74 37
04-08 23° 49° 1024 580 210 74 37
04-09 38° 60° 1051 598 217 74 37
04-10 35° 60° 1077 613 223 74 37
04-11 39° 57° 1103 630 229 74 37
04-12 33° 65° 1130 647 236 74 37
04-13 51° 75° 1171 678 257 87 45
04-14 49° 62° 1204 701 270 92 46
04-15 43° 59° 1233 720 280 93 46
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-16 33° 66° 1261 738 287 93 46
04-17 54° 70° 1301 768 307 105 53
04-18 53° 72° 1342 798 328 118 60
04-19 45° 59° 1371 818 337 119 60
04-20 45° 54° 1398 835 345 119 60
04-21 45° 61° 1429 856 356 122 60
04-22 44° 71° 1465 882 371 130 63
04-23 57° 76° 1509 916 396 146 74
04-24 59° 77° 1555 952 422 164 87
04-25 52° 63° 1591 978 437 172 90
04-26 44° 64° 1623 1000 449 176 90
04-27 44° 68° 1657 1024 463 182 91
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
04-28 56° 79° 1703 1060 489 200 104
04-29 48° 74° 1742 1089 508 211 110
04-30 44° 65° 1774 1111 520 215 110
05-01 53° 64° 1811 1137 537 224 113
05-02 47° 58° 1841 1158 547 226 113
05-03 46° 58° 1872 1178 558 228 113
05-04 41° 70° 1905 1202 571 234 114
05-05 44° 69° 1940 1226 586 240 115
05-06 44° 76° 1978 1254 604 250 120
05-07 54° 81° 2023 1290 629 268 133
05-08 50° 72° 2062 1319 648 279 139
05-09 41° 72° 2097 1344 663 286 141
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-10 50° 84° 2142 1379 688 303 153
05-11 47° 80° 2184 1411 710 317 162
05-12 53° 83° 2230 1447 736 335 175
05-13 60° 82° 2279 1486 765 356 191
05-14 59° 85° 2330 1526 796 378 208
05-15 68° 89° 2386 1573 833 407 232
05-16 58° 82° 2434 1611 860 427 247
05-17 50° 66° 2470 1637 876 435 250
05-18 44° 74° 2507 1664 893 444 254
05-19 49° 63° 2541 1688 908 450 255
05-20 51° 68° 2579 1715 925 460 260
05-21 52° 57° 2611 1738 937 464 260
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
05-22 47° 63° 2645 1761 951 469 260
05-23 44° 70° 2680 1787 966 477 262
05-24 53° 70° 2719 1816 986 488 269
05-25 56° 64° 2758 1844 1004 498 274
05-26 47° 71° 2794 1871 1021 507 278
05-27 57° 73° 2838 1904 1044 522 288
05-28 57° 66° 2877 1934 1063 534 294
05-29 55° 71° 2918 1965 1085 547 303
05-30 54° 80° 2963 2000 1109 564 315
05-31 56° 84° 3011 2038 1138 584 330
06-01 54° 77° 3055 2072 1161 600 341
06-02 55° 88° 3104 2111 1191 621 357
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-03 63° 80° 3154 2150 1220 642 373
06-04 60° 74° 3198 2185 1244 659 385
06-05 56° 78° 3243 2220 1269 676 396
06-06 62° 79° 3292 2258 1298 696 412
06-07 59° 75° 3336 2293 1323 713 424
06-08 56° 78° 3382 2328 1348 731 436
06-09 54° 71° 3422 2359 1369 743 444
06-10 50° 81° 3466 2393 1393 759 455
06-11 63° 92° 3522 2438 1428 787 477
06-12 65° 86° 3575 2482 1461 812 498
06-13 63° 80° 3625 2521 1491 833 514
06-14 65° 83° 3677 2563 1523 857 533
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-15 69° 81° 3730 2606 1556 883 553
06-16 67° 86° 3784 2651 1590 909 574
06-17 66° 90° 3840 2696 1626 936 597
06-18 68° 74° 3889 2735 1655 957 613
06-19 61° 85° 3940 2776 1686 981 631
06-20 67° 87° 3995 2822 1721 1008 653
06-21 77° 93° 4058 2875 1764 1043 684
06-22 77° 92° 4121 2927 1807 1077 713
06-23 75° 93° 4182 2979 1848 1111 742
06-24 72° 83° 4238 3025 1884 1139 764
06-25 73° 89° 4297 3074 1923 1170 790
06-26 71° 90° 4356 3122 1962 1200 816
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
06-27 71° 81° 4409 3166 1996 1226 837
06-28 66° 90° 4466 3212 2032 1254 860
06-29 72° 86° 4522 3259 2069 1283 884
06-30 69° 85° 4577 3304 2103 1310 905
07-01 64° 85° 4630 3347 2136 1335 925
07-02 64° 87° 4683 3390 2170 1360 946
07-03 66° 89° 4739 3436 2205 1388 968
07-04 73° 90° 4799 3485 2245 1419 995
07-05 73° 88° 4857 3534 2283 1450 1020
07-06 71° 86° 4914 3580 2320 1479 1044
07-07 69° 85° 4969 3625 2355 1506 1066
07-08 72° 83° 5024 3671 2391 1533 1089
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
07-09 68° 87° 5080 3717 2426 1561 1111
07-10 70° 88° 5137 3764 2463 1590 1135
07-11 67° 84° 5191 3807 2497 1616 1156
07-12 68° 82° 5244 3851 2530 1641 1176
07-13 62° 82° 5294 3891 2560 1663 1193
07-14 64° 85° 5346 3933 2593 1687 1213
07-15 65° 88° 5401 3978 2627 1714 1234
07-16 72° 84° 5457 4024 2663 1742 1257
07-17 63° 72° 5503 4059 2689 1759 1270
07-18 61° 80° 5551 4098 2717 1780 1285
07-19 70° 87° 5607 4144 2754 1808 1309
07-20 72° 84° 5663 4190 2789 1836 1332
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
07-21 68° 79° 5715 4231 2821 1859 1350
07-22 73° 88° 5773 4280 2859 1890 1376
07-23 77° 91° 5836 4332 2902 1924 1405
07-24 71° 83° 5891 4377 2937 1952 1427
07-25 71° 83° 5946 4423 2972 1979 1449
07-26 72° 84° 6002 4469 3009 2007 1473
07-27 73° 89° 6061 4518 3048 2038 1499
07-28 69° 89° 6119 4565 3085 2067 1523
07-29 70° 90° 6177 4613 3123 2098 1548
07-30 67° 79° 6228 4655 3154 2121 1566
07-31 63° 76° 6276 4692 3182 2140 1581
08-01 56° 77° 6320 4727 3206 2157 1592
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-02 59° 76° 6365 4762 3232 2174 1605
08-03 57° 77° 6410 4797 3256 2191 1617
08-04 60° 79° 6458 4834 3284 2211 1631
08-05 63° 82° 6508 4875 3314 2233 1649
08-06 62° 82° 6558 4915 3344 2255 1665
08-07 69° 84° 6613 4959 3379 2281 1687
08-08 70° 89° 6671 5007 3417 2311 1712
08-09 75° 86° 6729 5056 3455 2342 1737
08-10 73° 85° 6786 5103 3492 2371 1761
08-11 67° 80° 6838 5144 3524 2394 1780
08-12 69° 82° 6891 5188 3557 2420 1800
08-13 64° 81° 6942 5228 3588 2442 1818
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-14 61° 80° 6990 5267 3617 2463 1834
08-15 67° 89° 7046 5313 3652 2491 1857
08-16 70° 92° 7105 5362 3691 2522 1882
08-17 74° 91° 7166 5412 3732 2554 1910
08-18 72° 89° 7225 5461 3771 2585 1936
08-19 71° 83° 7279 5506 3806 2612 1958
08-20 70° 85° 7335 5551 3841 2639 1980
08-21 62° 78° 7383 5589 3869 2659 1995
08-22 62° 80° 7432 5628 3898 2681 2011
08-23 62° 75° 7478 5665 3924 2699 2024
08-24 54° 73° 7520 5696 3946 2712 2033
08-25 50° 70° 7558 5724 3964 2723 2038
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
08-26 48° 73° 7597 5753 3983 2733 2044
08-27 51° 73° 7636 5783 4002 2745 2050
08-28 58° 82° 7684 5821 4030 2765 2065
08-29 60° 80° 7732 5859 4058 2785 2080
08-30 63° 78° 7781 5897 4087 2805 2096
08-31 60° 77° 7827 5934 4114 2824 2110
09-01 56° 77° 7872 5969 4138 2841 2121
09-02 56° 79° 7917 6004 4164 2858 2134
09-03 57° 70° 7959 6035 4185 2872 2142
09-04 45° 68° 7993 6060 4199 2878 2143
09-05 50° 65° 8028 6085 4215 2885 2146
09-06 43° 67° 8061 6108 4227 2890 2146
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
09-07 41° 70° 8094 6131 4241 2895 2146
09-08 47° 75° 8134 6160 4260 2906 2152
09-09 51° 77° 8176 6192 4282 2921 2161
09-10 54° 82° 8222 6229 4308 2939 2175
09-11 56° 85° 8270 6267 4337 2959 2190
09-12 58° 89° 8322 6309 4368 2983 2209
09-13 68° 96° 8382 6359 4408 3015 2236
09-14 66° 94° 8440 6407 4446 3045 2261
09-15 69° 89° 8497 6454 4483 3074 2285
09-16 64° 90° 8552 6499 4518 3101 2307
09-17 63° 88° 8605 6542 4552 3126 2327
09-18 67° 73° 8653 6580 4579 3146 2342
2025Lo
(F)		Hi
(F)		GDD
22		GDD
32		GDD
42		GDD
50		GDD
55
09-19 64° 80° 8703 6620 4609 3168 2359
09-20 60° 76° 8749 6656 4635 3186 2372
09-21 60° 78° 8796 6693 4662 3205 2386
09-22 62° 83° 8847 6734 4693 3228 2404
09-23 60° 75° 8892 6769 4718 3245 2416
09-24 59° 77° 8939 6805 4745 3263 2429
09-25 51° 79° 8982 6838 4768 3279 2439
09-26 52° 87° 9029 6876 4795 3298 2454
09-27 56° 87° 9079 6915 4825 3319 2470
09-28 60° 87° 9130 6957 4856 3343 2489
09-29 56° 88° 9180 6997 4886 3365 2506
09-30 58° 88° 9231 7038 4918 3388 2524
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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