Average dates for the Last Effective Flower at key locations for different times when crops are anticipated to be finished (Last Harvestable Boll).
Estimates are based on a cotton boll development rate function, combined with frost risk analysis, leveraging 30 years of historical climate data from the State of Queensland’s SILO patched point dataset.
A key observation, particularly for cooler growing regions, is that as the date of LHB is delayed, the time of LEF is not increasingly delayed.
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Mean date of Last Effective Flower (LEF)Desired date for your crop to be finished(Last Harvestable Boll – LHB is mature) |
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| Location |
14th March |
21st March |
28th March |
7th April |
14th April |
21st April |
28th April |
7th May |
14th May |
Average First Frost Date |
Earliest Recorded Frost Date |
20th Percentile Frost Date |
80th Percentile Frost Date |
Latest Recorded 1st Frost Date |
| Jerilderie |
25-Jan
|
29-Jan
|
2-Feb
|
8-Feb
|
11-Feb
|
15-Feb
|
17-Feb
|
21-Feb
|
23-Feb
|
17-May
|
22-Apr
|
5-May
|
30-May
|
20-Jun
|
| Griffith |
26-Jan
|
31-Jan
|
5-Feb
|
10-Feb
|
13-Feb
|
17-Feb
|
19-Feb
|
23-Feb
|
25-Feb
|
16-May
|
22-Apr
|
2-May
|
30-May
|
20-Jun
|
| Hay |
26-Jan
|
31-Jan
|
4-Feb
|
10-Feb
|
13-Feb
|
16-Feb
|
19-Feb
|
22-Feb
|
25-Feb
|
16-May
|
13-Apr
|
1-May
|
30-May
|
13-Jul
|
| Hillston |
28-Jan
|
1-Feb
|
6-Feb
|
12-Feb
|
15-Feb
|
18-Feb
|
21-Feb
|
25-Feb
|
28-Feb
|
15-May
|
22-Apr
|
4-May
|
30-May
|
18-Jun
|
| Warren |
28-Jan
|
2-Feb
|
6-Feb
|
13-Feb
|
17-Feb
|
21-Feb
|
24-Feb
|
28-Feb
|
3-Mar
|
31-May
|
22-Apr
|
13-May
|
14-Jun
|
18-Jul
|
| Narromine |
26-Jan
|
31-Jan
|
5-Feb
|
11-Feb
|
15-Feb
|
18-Feb
|
21-Feb
|
25-Feb
|
28-Feb
|
17-May
|
22-Apr
|
7-May
|
27-May
|
18-Jun
|
| Bourke |
30-Jan
|
5-Feb
|
10-Feb
|
17-Feb
|
21-Feb
|
25-Feb
|
1-Mar
|
5-Mar
|
8-Mar
|
1-Jun
|
30-Apr
|
15-May
|
13-Jun
|
27-Jul
|
| Walgett |
29-Jan
|
4-Feb
|
9-Feb
|
15-Feb
|
19-Feb
|
22-Feb
|
26-Feb
|
3-Mar
|
6-Mar
|
23-May
|
30-Apr
|
9-May
|
31-May
|
18-Jun
|
| Wee Waa |
27-Jan
|
2-Feb
|
7-Feb
|
14-Feb
|
18-Feb
|
22-Feb
|
25-Feb
|
2-Mar
|
5-Mar
|
23-May
|
28-Apr
|
9-May
|
4-Jun
|
18-Jun
|
| Narrabri |
27-Jan
|
2-Feb
|
6-Feb
|
12-Feb
|
17-Feb
|
21-Feb
|
25-Feb
|
1-Mar
|
4-Mar
|
19-May
|
22-Apr
|
6-May
|
29-May
|
24-Jun
|
| Gunnedah |
24-Jan
|
30-Jan
|
4-Feb
|
9-Feb
|
13-Feb
|
17-Feb
|
21-Feb
|
25-Feb
|
28-Feb
|
14-May
|
12-Apr
|
4-May
|
24-May
|
18-Jun
|
| Quirindi |
22-Jan
|
27-Jan
|
31-Jan
|
7-Feb
|
10-Feb
|
15-Feb
|
18-Feb
|
22-Feb
|
25-Feb
|
7-May
|
5-Apr
|
26-Apr
|
20-May
|
28-May
|
| Burren Junction |
28-Jan
|
2-Feb
|
7-Feb
|
14-Feb
|
18-Feb
|
22-Feb
|
26-Feb
|
2-Mar
|
6-Mar
|
24-May
|
30-Apr
|
10-May
|
6-Jun
|
18-Jun
|
| Spring Ridge |
23-Jan
|
29-Jan
|
3-Feb
|
8-Feb
|
12-Feb
|
17-Feb
|
20-Feb
|
24-Feb
|
27-Feb
|
12-May
|
12-Apr
|
5-May
|
23-May
|
18-Jun
|
| Moree |
27-Jan
|
2-Feb
|
7-Feb
|
13-Feb
|
17-Feb
|
21-Feb
|
25-Feb
|
2-Mar
|
6-Mar
|
26-May
|
23-Apr
|
14-May
|
11-Jun
|
27-Jun
|
| Mungindi |
29-Jan
|
4-Feb
|
9-Feb
|
16-Feb
|
20-Feb
|
24-Feb
|
28-Feb
|
5-Mar
|
9-Mar
|
5-Jun
|
1-May
|
16-May
|
25-Jun
|
10-Jul
|
| St George |
29-Jan
|
4-Feb
|
9-Feb
|
16-Feb
|
20-Feb
|
25-Feb
|
1-Mar
|
6-Mar
|
10-Mar
|
3-Jun
|
1-May
|
16-May
|
15-Jun
|
21-Aug
|
| Goondiwindi |
28-Jan
|
3-Feb
|
7-Feb
|
14-Feb
|
18-Feb
|
23-Feb
|
27-Feb
|
4-Mar
|
8-Mar
|
26-May
|
28-Apr
|
14-May
|
8-Jun
|
30-Jun
|
| Dalby |
24-Jan
|
29-Jan
|
4-Feb
|
12-Feb
|
16-Feb
|
20-Feb
|
25-Feb
|
2-Mar
|
5-Mar
|
20-May
|
28-Apr
|
8-May
|
29-May
|
26-Jun
|
| Forest Hill |
21-Jan
|
27-Jan
|
2-Feb
|
9-Feb
|
14-Feb
|
19-Feb
|
24-Feb
|
28-Feb
|
4-Mar
|
14-Jun
|
9-May
|
31-May
|
27-Jun
|
18-Jul
|
| Murgon |
21-Jan
|
27-Jan
|
1-Feb
|
10-Feb
|
14-Feb
|
19-Feb
|
23-Feb
|
28-Feb
|
4-Mar
|
28-May
|
1-May
|
15-May
|
9-Jun
|
26-Jun
|
| Maryborough |
23-Jan
|
29-Jan
|
3-Feb
|
12-Feb
|
17-Feb
|
22-Feb
|
27-Feb
|
5-Mar
|
9-Mar
|
14-Jul
|
10-Jun
|
29-Jun
|
1-Aug
|
26-Aug
|
| Theodore |
27-Jan
|
3-Feb
|
8-Feb
|
16-Feb
|
20-Feb
|
26-Feb
|
3-Mar
|
8-Mar
|
12-Mar
|
7-Jun
|
10-May
|
20-May
|
24-Jun
|
4-Jul
|
| Emerald |
29-Jan
|
4-Feb
|
10-Feb
|
18-Feb
|
23-Feb
|
1-Mar
|
6-Mar
|
12-Mar
|
16-Mar
|
11-Jul
|
30-May
|
20-Jun
|
9-Aug
|
20-Aug
|
| 30-year historical record mean data | 30-year historical record data | |||||||||||||
| Last effective flower/cutout date estimated using a boll period that has fibre mature in the boll. This is the estimated date, that on average when analysing the climate record, indicates the date of the last effective flower for desired date of crop maturity. |
Historical record dates of average first frost, earliest recorded, 20th and 80th percentile and latest recorded as analysed via the SILO dataset. | |||||||||||||
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Climate observation data obtained via the State of Queensland SILO patched point dataset. General guide only. Not comprehensive or specific technical advice. Circumstances vary from farm to farm. To the fullest extent permitted by law, CSD expressly disclaims liability for any loss or damage arising from reliance upon any information, statement or opinion on this website or from any errors or omissions on this website. |
20th percentile indicates 80% of the time first frost occurred after this date. —————————————————————- 80th percentile indicates 20% of the time first frost occurred after this date. |
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