Bathurst
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bathurst clear sky chart from 2005-11-06 to 2024-02-20.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
21%
23244
13%
80809
5%
23133
31%
23133
13%
56118

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 10thNight
13%
837
12%
4697
1%
817
22%
817
5%
3073
January11th to 20thNight
13%
833
13%
4641
1%
808
24%
808
6%
3288
January21st to endNight
18%
830
13%
4646
6%
814
34%
814
10%
2687
February1st to 10thNight
18%
760
16%
2470
4%
760
34%
760
13%
1711
February11th to 20thNight
13%
742
12%
2400
2%
739
26%
739
10%
1754
February21st to endNight
16%
592
16%
1884
3%
592
32%
592
14%
1339
March1st to 10thNight
16%
720
18%
2049
5%
720
28%
720
14%
1503
March11th to 20thNight
20%
720
15%
1980
5%
720
28%
720
16%
1442
March21st to endNight
18%
792
17%
2178
4%
792
31%
792
16%
1593
April1st to 10thNight
18%
590
13%
1819
4%
590
27%
590
12%
1347
April11th to 20thNight
20%
534
17%
1598
7%
534
30%
534
17%
1128
April21st to endNight
23%
540
15%
1620
7%
540
31%
540
15%
1189
May1st to 10thNight
24%
540
13%
1556
7%
540
31%
540
17%
1138
May11th to 20thNight
25%
532
14%
1417
6%
532
33%
532
20%
1021
May21st to endNight
23%
463
12%
1432
3%
463
32%
463
17%
988
June1st to 10thNight
28%
360
8%
1260
3%
360
34%
360
15%
902
June11th to 20thNight
36%
360
10%
1260
5%
360
42%
360
19%
829
June21st to endNight
28%
360
6%
1260
3%
360
31%
360
14%
917
July1st to 10thNight
30%
350
10%
1225
4%
350
39%
350
20%
802
July11th to 20thNight
37%
348
11%
1218
8%
348
43%
348
23%
798
July21st to endNight
37%
461
12%
1407
9%
436
43%
436
19%
956
August1st to 10thNight
35%
538
9%
1600
6%
534
39%
534
22%
1083
August11th to 20thNight
39%
532
13%
1596
8%
532
45%
532
22%
1104
August21st to endNight
39%
594
19%
1782
9%
594
47%
594
27%
1110
September1st to 10thNight
30%
540
17%
1795
8%
540
41%
540
22%
1108
September11th to 20thNight
31%
682
20%
1942
10%
682
41%
682
28%
1212
September21st to endNight
30%
720
22%
1984
9%
720
41%
720
26%
1285
October1st to 10thNight
27%
720
19%
2160
8%
720
38%
720
20%
1458
October11th to 20thNight
20%
720
17%
2160
5%
720
31%
720
16%
1513
October21st to endNight
19%
792
14%
2488
4%
792
29%
792
13%
1764
November1st to 10thNight
18%
818
15%
2570
5%
818
28%
818
13%
1830
November11th to 20thNight
15%
850
14%
2660
4%
850
26%
850
11%
1974
November21st to endNight
16%
850
10%
2660
2%
850
25%
850
9%
2030
December1st to 10thNight
13%
850
12%
2740
2%
850
24%
850
10%
2056
December11th to 20thNight
10%
850
10%
3484
3%
849
20%
849
6%
2720
December21st to endNight
10%
924
8%
5171
1%
907
21%
907
5%
3466

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
17%8%36%6%45%5%5%6%34%
77919
Night
17%9%36%5%35%5%5%6%35%
81284
TransparencyDay
50%6%12%20%10%1
77609
Night
50%7%12%20%10%1
81129
SeeingDay
27%17%30%18%7%2
15402
Night
25%16%31%21%6%1
23279

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
13%10%49%8%45%5%46%32%
2207
11th to 20thDay
12%10%47%11%5%7%6%5%7%25%
2245
21st to endDay
7%7%37%6%45%6%6%7%42%
2933
February1st to 10thDay
10%12%5%7%6%46%6%6%7%32%
1710
11th to 20thDay
13%13%5%9%7%45%5%5%6%28%
1654
21st to endDay
11%11%5%9%445%5%5%7%35%
1368
March1st to 10thDay
15%14%6%6%5%45%5%5%5%30%
1906
11th to 20thDay
15%9%47%7%35%5%5%6%33%
1980
21st to endDay
16%12%46%5%34345%37%
2178
April1st to 10thDay
20%10%5%8%6%3345%7%29%
2137
11th to 20thDay
20%9%25%4245%5%6%38%
2312
21st to endDay
25%10%46%5%3435%5%30%
2340
May1st to 10thDay
23%10%36%6%35%345%31%
2402
11th to 20thDay
23%8%35%5%3445%6%33%
2478
21st to endDay
20%6%36%6%4445%7%35%
2857
June1st to 10thDay
25%7%36%5%35%45%8%30%
2700
11th to 20thDay
19%6%35%6%45%5%6%7%35%
2700
21st to endDay
25%7%37%6%45%5%5%7%26%
2700
July1st to 10thDay
17%6%37%7%46%6%6%8%30%
2700
11th to 20thDay
11%6%36%7%46%7%6%9%34%
2700
21st to endDay
18%7%35%6%46%5%6%8%32%
2804
August1st to 10thDay
15%7%36%5%45%7%7%8%33%
2327
11th to 20thDay
15%6%26%7%45%6%6%6%35%
2304
21st to endDay
13%5%36%6%45%5%5%7%41%
2574
September1st to 10thDay
16%5%25%5%4446%7%41%
2164
11th to 20thDay
18%5%35%43444445%
2016
21st to endDay
18%5%25%5%345%6%6%41%
1976
October1st to 10thDay
15%6%36%6%45%446%43%
1800
11th to 20thDay
20%7%36%5%35%5%5%6%35%
1800
21st to endDay
24%8%36%43445%6%33%
1865
November1st to 10thDay
18%8%37%5%5%6%5%5%7%32%
1508
11th to 20thDay
20%9%37%5%45%5%5%6%31%
1520
21st to endDay
17%12%48%6%35%5%6%7%28%
1520
December1st to 10thDay
21%11%47%5%36%5%5%6%29%
1435
11th to 20thDay
16%12%49%7%5%6%45%5%26%
1668
21st to endDay
17%12%47%6%35%44435%
2431
January1st to 10thNight
10%9%48%7%45%6%7%8%32%
4748
11th to 20thNight
16%10%48%7%45%5%5%6%30%
4722
21st to endNight
8%11%36%5%345%6%8%40%
4721
February1st to 10thNight
10%14%45%5%35%5%5%8%34%
2470
11th to 20thNight
14%15%47%6%35%45%5%30%
2397
21st to endNight
13%13%5%7%6%36%5%5%6%32%
1884
March1st to 10thNight
16%13%47%6%35%445%32%
2040
11th to 20thNight
16%9%46%5%45%6%5%6%34%
1979
21st to endNight
16%11%47%6%35%44435%
2178
April1st to 10thNight
25%10%46%5%34346%30%
1819
11th to 20thNight
22%8%36%5%3445%5%35%
1598
21st to endNight
25%11%35%5%33346%32%
1620
May1st to 10thNight
23%8%26%6%45%35%6%32%
1556
11th to 20thNight
22%7%35%6%35%5%5%6%35%
1416
21st to endNight
19%7%35%435%5%5%8%37%
1431
June1st to 10thNight
23%10%25%435%5%5%6%32%
1260
11th to 20thNight
20%5%35%435%6%6%6%37%
1260
21st to endNight
22%7%47%6%46%447%30%
1260
July1st to 10thNight
16%7%26%5%35%46%8%38%
1260
11th to 20thNight
11%5%36%5%46%6%6%9%38%
1260
21st to endNight
15%7%36%5%36%5%6%8%36%
1489
August1st to 10thNight
16%5%35%6%46%45%7%39%
1612
11th to 20thNight
15%6%26%6%35%6%7%7%37%
1596
21st to endNight
10%5%25%5%445%6%7%46%
1782
September1st to 10thNight
17%5%2343445%8%45%
1795
11th to 20thNight
15%6%25%42335%7%48%
1942
21st to endNight
17%32443445%6%47%
1984
October1st to 10thNight
19%5%25%5%34446%42%
2160
11th to 20thNight
19%8%36%6%35%35%6%38%
2160
21st to endNight
23%8%35%5%3445%7%35%
2488
November1st to 10thNight
21%8%36%5%345%5%6%35%
2570
11th to 20thNight
19%10%47%6%35%45%6%31%
2660
21st to endNight
20%10%36%5%45%5%5%7%30%
2660
December1st to 10thNight
21%11%46%5%3445%6%31%
2740
11th to 20thNight
19%13%37%6%45%5%5%5%26%
3531
21st to endNight
18%11%47%6%34445%33%
5236

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
54%8%12%15%10%1
2208
11th to 20thDay
56%10%8%15%11%
2245
21st to endDay
40%9%13%24%13%1
2933
February1st to 10thDay
50%6%12%19%11%2
1710
11th to 20thDay
58%5%10%18%9%1
1662
21st to endDay
50%49%22%12%3
1368
March1st to 10thDay
55%5%10%19%10%2
1910
11th to 20thDay
52%5%11%19%11%3
1980
21st to endDay
51%410%19%14%3
2178
April1st to 10thDay
57%310%16%12%2
2137
11th to 20thDay
47%412%21%14%2
2312
21st to endDay
57%5%8%14%12%4
2340
May1st to 10thDay
56%48%19%11%2
2402
11th to 20thDay
51%6%10%20%12%1
2482
21st to endDay
49%6%11%22%12%1
2857
June1st to 10thDay
54%5%11%18%11%1
2700
11th to 20thDay
47%6%13%21%11%2
2700
21st to endDay
58%7%11%16%8%
2700
July1st to 10thDay
50%7%16%18%8%
2625
11th to 20thDay
44%8%15%22%10%1
2619
21st to endDay
49%8%15%20%8%
2646
August1st to 10thDay
48%7%16%22%7%
2314
11th to 20thDay
47%7%18%20%8%
2304
21st to endDay
42%7%15%27%10%
2574
September1st to 10thDay
42%6%14%25%13%
2164
11th to 20thDay
43%5%12%25%15%1
2016
21st to endDay
43%7%11%25%13%1
1976
October1st to 10thDay
43%5%13%27%11%1
1800
11th to 20thDay
49%7%14%22%8%
1800
21st to endDay
53%6%12%18%11%1
1865
November1st to 10thDay
52%7%11%20%9%1
1508
11th to 20thDay
54%8%13%15%9%1
1520
21st to endDay
57%10%13%16%5%
1520
December1st to 10thDay
58%9%11%16%7%
1435
11th to 20thDay
61%7%10%14%8%1
1668
21st to endDay
53%7%13%15%9%3
2431
January1st to 10thNight
48%11%17%18%5%
4748
11th to 20thNight
54%9%10%16%10%
4722
21st to endNight
42%7%14%23%14%1
4721
February1st to 10thNight
49%6%12%18%13%2
2470
11th to 20thNight
55%5%9%18%11%1
2400
21st to endNight
54%48%19%13%2
1884
March1st to 10thNight
55%47%21%12%1
2049
11th to 20thNight
52%6%9%20%12%2
1980
21st to endNight
52%5%8%18%13%3
2178
April1st to 10thNight
57%48%15%14%2
1819
11th to 20thNight
51%5%9%18%15%2
1598
21st to endNight
54%5%7%16%14%3
1620
May1st to 10thNight
54%49%18%13%2
1556
11th to 20thNight
49%6%10%22%12%1
1417
21st to endNight
46%8%12%21%12%1
1432
June1st to 10thNight
53%6%10%19%11%1
1260
11th to 20thNight
46%6%12%24%11%2
1260
21st to endNight
56%6%13%16%9%1
1260
July1st to 10thNight
44%7%17%24%8%
1225
11th to 20thNight
41%9%15%25%9%1
1218
21st to endNight
45%8%15%23%9%
1407
August1st to 10thNight
45%7%17%24%7%
1600
11th to 20thNight
44%9%20%22%5%
1596
21st to endNight
36%7%17%29%11%
1782
September1st to 10thNight
38%7%13%30%11%1
1795
11th to 20thNight
37%5%14%29%14%1
1942
21st to endNight
38%7%12%29%14%1
1984
October1st to 10thNight
44%6%11%25%12%1
2160
11th to 20thNight
49%7%12%25%8%
2160
21st to endNight
50%7%14%20%9%1
2488
November1st to 10thNight
50%8%13%20%9%1
2570
11th to 20thNight
54%8%12%17%8%1
2660
21st to endNight
56%10%14%15%5%1
2660
December1st to 10thNight
54%9%12%18%6%
2740
11th to 20thNight
60%9%9%16%6%
3532
21st to endNight
54%6%15%16%7%1
5236

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
31%18%31%16%31
180
11th to 20thDay
36%19%26%12%6%1
180
21st to endDay
21%18%34%21%5%1
294
February1st to 10thDay
25%26%26%15%6%2
370
11th to 20thDay
25%28%29%15%31
363
21st to endDay
22%22%35%17%41
296
March1st to 10thDay
31%18%33%14%31
420
11th to 20thDay
29%18%29%16%6%2
420
21st to endDay
28%24%29%12%7%1
462
April1st to 10thDay
37%20%29%11%31
420
11th to 20thDay
30%19%29%17%5%1
412
21st to endDay
35%19%25%14%5%2
420
May1st to 10thDay
33%16%28%17%5%1
485
11th to 20thDay
29%16%27%16%9%2
624
21st to endDay
30%16%30%17%6%
680
June1st to 10thDay
33%12%28%18%7%2
630
11th to 20thDay
25%16%28%22%8%2
630
21st to endDay
27%13%29%22%8%2
630
July1st to 10thDay
20%14%32%22%10%1
620
11th to 20thDay
13%12%36%28%8%2
618
21st to endDay
21%10%31%25%12%2
636
August1st to 10thDay
17%13%33%25%10%2
446
11th to 20thDay
19%11%30%27%11%2
439
21st to endDay
19%11%29%27%11%2
495
September1st to 10thDay
17%18%32%23%8%2
450
11th to 20thDay
24%18%29%19%7%2
450
21st to endDay
26%19%31%14%8%3
448
October1st to 10thDay
18%20%28%20%11%4
360
11th to 20thDay
29%20%28%14%8%2
360
21st to endDay
35%23%21%14%6%1
396
November1st to 10thDay
30%22%28%14%5%1
365
11th to 20thDay
32%19%29%14%5%1
370
21st to endDay
32%21%31%12%31
370
December1st to 10thDay
35%15%30%15%41
285
11th to 20thDay
32%28%27%12%21
180
21st to endDay
35%20%29%13%2
198
January1st to 10thNight
25%20%33%18%4
850
11th to 20thNight
28%19%34%15%4
837
21st to endNight
20%21%35%19%4
836
February1st to 10thNight
21%22%32%19%5%1
760
11th to 20thNight
29%20%31%15%41
742
21st to endNight
22%17%37%18%6%
592
March1st to 10thNight
26%18%33%19%3
720
11th to 20thNight
26%15%35%17%6%1
720
21st to endNight
23%18%33%20%6%1
792
April1st to 10thNight
32%16%29%18%4
590
11th to 20thNight
28%15%31%18%8%
534
21st to endNight
32%14%23%23%7%1
540
May1st to 10thNight
27%12%29%25%7%
540
11th to 20thNight
26%14%30%22%8%
532
21st to endNight
23%15%34%23%5%
464
June1st to 10thNight
29%9%26%29%6%
360
11th to 20thNight
21%9%28%31%10%1
360
21st to endNight
24%9%28%28%9%1
360
July1st to 10thNight
19%9%35%26%11%1
350
11th to 20thNight
12%7%38%35%7%1
348
21st to endNight
17%9%30%32%12%
461
August1st to 10thNight
18%7%31%33%10%
538
11th to 20thNight
16%9%26%36%12%
532
21st to endNight
14%9%31%32%13%1
594
September1st to 10thNight
19%14%34%25%9%
540
11th to 20thNight
21%11%31%25%10%1
682
21st to endNight
21%13%33%25%8%
720
October1st to 10thNight
23%16%30%22%8%1
720
11th to 20thNight
25%17%33%17%8%
720
21st to endNight
31%20%26%19%4
792
November1st to 10thNight
30%19%28%18%5%
818
11th to 20thNight
29%20%30%14%5%2
850
21st to endNight
30%19%30%17%4
850
December1st to 10thNight
30%19%32%14%4
850
11th to 20thNight
32%24%29%10%4
850
21st to endNight
31%21%29%16%21
935
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