Bathurst
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bathurst clear sky chart from 2005-11-05 to 2017-12-04.

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
22%
15047
13%
47749
5%
15011
32%
15011
15%
34035

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 15thNight
12%
750
10%
2685
1%
746
22%
746
8%
2005
January16th to endNight
16%
775
17%
2671
4%
775
32%
775
14%
1813
February1st to 15thNight
21%
704
13%
2286
3%
701
34%
701
14%
1614
February16th to endNight
15%
631
11%
2024
2%
631
26%
631
10%
1537
March1st to 15thNight
18%
720
17%
2026
6%
720
28%
720
15%
1481
March16th to endNight
20%
768
19%
2112
5%
768
32%
768
18%
1502
April1st to 15thNight
22%
572
15%
1749
7%
572
30%
572
15%
1269
April16th to endNight
23%
540
16%
1620
8%
540
31%
540
17%
1155
May1st to 15thNight
29%
540
11%
1517
6%
540
34%
540
17%
1125
May16th to endNight
23%
479
10%
1415
3%
479
30%
479
15%
1047
June1st to 15thNight
31%
360
6%
1260
3%
360
34%
360
14%
905
June16th to endNight
31%
360
5%
1260
3%
360
34%
360
14%
901
July1st to 15thNight
36%
340
9%
1190
6%
340
42%
340
22%
774
July16th to endNight
38%
421
10%
1311
8%
396
42%
396
20%
891
August1st to 15thNight
38%
539
9%
1608
5%
535
43%
535
20%
1115
August16th to endNight
39%
573
16%
1719
8%
573
46%
573
26%
1110
September1st to 15thNight
31%
575
16%
1832
8%
575
40%
575
23%
1147
September16th to endNight
30%
717
22%
1983
11%
717
41%
717
28%
1253
October1st to 15thNight
25%
720
18%
2160
6%
720
37%
720
20%
1455
October16th to endNight
18%
768
14%
2379
3%
768
28%
768
14%
1695
November1st to 15thNight
19%
801
15%
2648
5%
801
29%
801
12%
1893
November16th to endNight
18%
825
12%
2730
4%
825
28%
825
10%
2057
December1st to 15thNight
11%
769
10%
2684
1%
769
21%
769
8%
2021
December16th to endNight
9%
800
9%
2880
1%
800
18%
800
6%
2270

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
19%8%36%5%3445%6%32%
48757
Night
18%8%35%5%3445%6%34%
47905
TransparencyDay
52%5%12%18%9%
48431
Night
50%6%11%20%9%
47749
SeeingDay
26%14%29%19%7%1
7185
Night
25%15%30%21%7%
15048

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 15thDay
13%12%47%7%3445%7%29%
1253
16th to endDay
13%8%36%6%345%5%6%35%
1551
February1st to 15thDay
9%12%5%7%5%36%5%6%7%30%
1575
16th to endDay
14%14%48%5%45%445%27%
1446
March1st to 15thDay
17%10%5%5%6%35%5%45%30%
1922
16th to endDay
15%10%35%5%34345%38%
2112
April1st to 15thDay
20%9%36%4345%46%31%
2198
16th to endDay
26%7%34423336%34%
2340
May1st to 15thDay
23%8%35%5%34345%30%
2434
16th to endDay
24%7%36%5%3445%6%28%
2708
June1st to 15thDay
23%7%35%43445%6%31%
2700
16th to endDay
25%6%36%6%45%45%6%26%
2700
July1st to 15thDay
15%5%35%7%46%5%6%8%29%
2700
16th to endDay
19%6%35%6%45%5%5%7%30%
2751
August1st to 15thDay
17%7%25%5%45%6%6%7%31%
2340
16th to endDay
14%426%7%345%5%6%38%
2483
September1st to 15thDay
18%425%5%3345%6%40%
2127
16th to endDay
17%42442345%6%44%
1976
October1st to 15thDay
16%6%25%5%34346%40%
1800
16th to endDay
25%7%35%42434434%
1842
November1st to 15thDay
21%8%26%435%45%6%31%
1540
16th to endDay
18%11%47%4345%5%6%28%
1560
December1st to 15thDay
21%11%46%435%435%28%
1355
16th to endDay
20%13%48%5%25%44427%
1344
January1st to 15thNight
15%11%46%5%3445%6%30%
2685
16th to endNight
14%9%35%5%345%6%7%34%
2671
February1st to 15thNight
10%13%45%5%35%46%7%33%
2285
16th to endNight
15%16%46%6%26%445%27%
2024
March1st to 15thNight
18%9%46%5%25%445%32%
2014
16th to endNight
15%9%47%42444438%
2112
April1st to 15thNight
24%8%35%434345%31%
1749
16th to endNight
24%9%25%42233435%
1620
May1st to 15thNight
21%7%26%6%35%35%6%30%
1517
16th to endNight
23%7%25%4335%46%31%
1413
June1st to 15thNight
22%10%24425%6%5%6%30%
1260
16th to endNight
21%5%36%6%45%45%6%29%
1260
July1st to 15thNight
14%5%25%5%35%45%8%38%
1260
16th to endNight
16%6%25%5%26%5%6%8%36%
1400
August1st to 15thNight
18%5%145%35%45%7%36%
1620
16th to endNight
10%425%6%345%6%7%43%
1719
September1st to 15thNight
17%5%2442345%7%44%
1832
16th to endNight
16%213323346%49%
1983
October1st to 15thNight
18%5%15%434346%42%
2160
16th to endNight
23%7%3442335%6%34%
2379
November1st to 15thNight
22%8%35%424445%34%
2648
16th to endNight
18%10%36%5%3445%6%31%
2730
December1st to 15thNight
20%11%36%434445%30%
2684
16th to endNight
22%11%47%5%35%445%26%
2880

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 15thDay
56%8%11%13%10%
1254
16th to endDay
47%7%12%20%12%
1551
February1st to 15thDay
50%6%13%20%7%1
1578
16th to endDay
59%48%18%7%1
1446
March1st to 15thDay
55%49%18%10%2
1933
16th to endDay
48%410%21%13%2
2112
April1st to 15thDay
53%310%16%12%3
2198
16th to endDay
51%39%16%14%3
2340
May1st to 15thDay
55%48%18%11%1
2434
16th to endDay
56%5%11%17%7%
2712
June1st to 15thDay
53%5%11%16%10%1
2700
16th to endDay
58%6%12%14%7%
2700
July1st to 15thDay
49%6%16%18%9%
2541
16th to endDay
52%5%16%17%7%
2578
August1st to 15thDay
49%6%16%21%6%
2327
16th to endDay
44%6%17%23%7%
2483
September1st to 15thDay
45%414%24%10%
2127
16th to endDay
40%5%12%26%14%
1976
October1st to 15thDay
45%5%14%24%9%1
1800
16th to endDay
53%410%20%9%
1842
November1st to 15thDay
54%6%12%15%9%
1540
16th to endDay
55%10%12%15%5%
1560
December1st to 15thDay
59%9%11%13%4
1355
16th to endDay
61%8%10%13%5%
1344
January1st to 15thNight
54%10%12%14%7%
2685
16th to endNight
48%6%11%21%11%
2671
February1st to 15thNight
50%5%13%20%9%
2286
16th to endNight
60%48%15%10%1
2024
March1st to 15thNight
54%38%19%12%1
2026
16th to endNight
49%48%19%15%2
2112
April1st to 15thNight
54%47%16%13%3
1749
16th to endNight
53%37%16%15%3
1620
May1st to 15thNight
54%5%8%19%9%1
1517
16th to endNight
53%6%12%18%8%
1415
June1st to 15thNight
53%6%11%17%9%1
1260
16th to endNight
54%5%13%17%7%
1260
July1st to 15thNight
43%5%15%25%8%
1190
16th to endNight
45%7%16%21%8%
1311
August1st to 15thNight
46%7%17%21%5%
1608
16th to endNight
38%7%19%26%7%
1719
September1st to 15thNight
39%6%12%28%11%1
1832
16th to endNight
36%5%14%29%13%1
1983
October1st to 15thNight
44%6%11%27%9%1
2160
16th to endNight
51%5%12%21%8%
2379
November1st to 15thNight
52%6%12%18%8%
2648
16th to endNight
55%9%12%16%4
2730
December1st to 15thNight
55%9%12%17%4
2684
16th to endNight
61%9%7%14%6%
2880

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 15thDay
31%18%33%15%1
60
16th to endDay
23%13%37%18%6%
124
February1st to 15thDay
17%22%29%22%6%1
236
16th to endDay
27%17%30%18%41
216
March1st to 15thDay
30%18%26%17%5%1
270
16th to endDay
25%20%30%12%9%2
288
April1st to 15thDay
32%17%27%15%6%
270
16th to endDay
32%16%25%16%5%2
270
May1st to 15thDay
32%13%27%15%8%2
390
16th to endDay
32%14%27%18%6%
519
June1st to 15thDay
33%10%26%22%7%1
495
16th to endDay
27%12%28%22%7%2
495
July1st to 15thDay
19%10%33%24%8%2
475
16th to endDay
22%8%30%25%12%1
481
August1st to 15thDay
20%9%30%25%12%2
313
16th to endDay
18%8%29%27%12%2
332
September1st to 15thDay
20%12%34%23%8%1
315
16th to endDay
23%14%34%17%8%2
312
October1st to 15thDay
19%18%30%17%8%4
270
16th to endDay
38%18%26%10%6%
288
November1st to 15thDay
30%18%26%15%7%2
280
16th to endDay
29%16%31%17%31
285
December1st to 15thDay
38%13%26%16%4
137
16th to endDay
29%32%34%11
64
January1st to 15thNight
26%22%33%14%3
750
16th to endNight
23%17%37%17%3
775
February1st to 15thNight
20%18%33%21%5%
704
16th to endNight
27%17%30%16%7%
631
March1st to 15thNight
25%19%31%19%4
720
16th to endNight
21%16%33%20%6%1
768
April1st to 15thNight
31%13%29%18%6%
572
16th to endNight
30%13%26%21%7%
540
May1st to 15thNight
24%10%28%26%9%
540
16th to endNight
25%12%32%22%5%
480
June1st to 15thNight
28%7%25%30%6%
360
16th to endNight
24%7%27%27%11%1
360
July1st to 15thNight
15%6%34%30%12%
340
16th to endNight
18%7%29%33%11%
421
August1st to 15thNight
21%5%25%34%12%
539
16th to endNight
14%9%31%30%13%
573
September1st to 15thNight
20%13%30%25%9%
575
16th to endNight
20%11%34%25%7%
717
October1st to 15thNight
22%15%32%20%7%1
720
16th to endNight
30%19%28%17%4
768
November1st to 15thNight
28%16%30%15%7%1
801
16th to endNight
26%18%30%16%6%1
825
December1st to 15thNight
32%21%30%12%3
769
16th to endNight
33%18%30%13%31
800
Page generated at 2017-12-05 11:18:58. Version ac04

Copyright 2017 A. Danko


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