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 2026-08-15.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	16% 9% 3 8% 5% 5% 5% 4 6% 7% 33%	144478
	Night	16% 10% 3 8% 5% 4 4 4 5% 6% 34%	137646
Transparency	Day	51% 4 12% 21% 11% 1	147949
	Night	51% 5% 12% 21% 10% 1	142265
Seeing	Day	27% 17% 30% 18% 7% 2	18868
	Night	25% 16% 31% 21% 6% 1	26411

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	14% 17% 5% 11% 6% 5% 4 3 4 5% 26%	4093
	11th to 20th	Day	13% 12% 5% 12% 8% 6% 6% 4 5% 6% 22%	4158
	21st to end	Day	4 8% 3 10% 6% 5% 5% 6% 7% 7% 39%	5438
February	1st to 10th	Day	9% 12% 5% 9% 6% 6% 6% 4 6% 6% 32%	1890
	11th to 20th	Day	12% 15% 4 10% 6% 5% 5% 4 5% 5% 29%	1843
	21st to end	Day	10% 12% 5% 9% 5% 5% 5% 3 5% 7% 35%	1599
March	1st to 10th	Day	19% 13% 4 7% 4 4 5% 3 4 6% 31%	4873
	11th to 20th	Day	15% 15% 5% 10% 6% 5% 5% 4 5% 6% 25%	5090
	21st to end	Day	22% 12% 4 8% 5% 4 4 3 4 6% 28%	5587
April	1st to 10th	Day	20% 12% 4 8% 5% 4 3 3 5% 6% 30%	2495
	11th to 20th	Day	20% 9% 2 6% 4 4 5% 3 4 6% 36%	2702
	21st to end	Day	23% 10% 4 7% 4 4 4 3 5% 5% 31%	2730
May	1st to 10th	Day	24% 12% 4 8% 5% 5% 4 3 5% 5% 25%	7867
	11th to 20th	Day	21% 9% 3 7% 4 4 5% 4 5% 6% 32%	8220
	21st to end	Day	23% 8% 3 8% 5% 4 4 4 5% 6% 29%	9528
June	1st to 10th	Day	23% 8% 3 6% 4 4 5% 3 6% 7% 31%	3150
	11th to 20th	Day	19% 7% 3 5% 5% 5% 5% 4 6% 7% 34%	3150
	21st to end	Day	23% 8% 3 8% 6% 6% 5% 4 6% 6% 26%	3150
July	1st to 10th	Day	11% 6% 2 8% 5% 6% 6% 5% 7% 9% 34%	8880
	11th to 20th	Day	10% 6% 3 7% 6% 6% 6% 5% 7% 8% 37%	8880
	21st to end	Day	13% 5% 2 5% 4 5% 5% 4 6% 9% 43%	9179
August	1st to 10th	Day	13% 7% 2 7% 5% 5% 6% 5% 7% 8% 35%	4365
	11th to 20th	Day	14% 5% 2 7% 6% 6% 6% 5% 7% 8% 35%	4227
	21st to end	Day	15% 5% 2 6% 4 4 4 4 5% 7% 43%	4675
September	1st to 10th	Day	15% 5% 2 7% 4 5% 4 3 6% 7% 43%	2404
	11th to 20th	Day	16% 5% 3 6% 4 4 4 3 4 5% 46%	2239
	21st to end	Day	17% 5% 2 6% 4 5% 4 4 6% 7% 41%	2194
October	1st to 10th	Day	15% 6% 3 6% 5% 5% 4 3 5% 6% 43%	2000
	11th to 20th	Day	20% 8% 3 7% 4 5% 5% 4 5% 6% 34%	2000
	21st to end	Day	23% 8% 3 6% 3 4 4 3 5% 6% 33%	2071
November	1st to 10th	Day	18% 9% 3 7% 5% 6% 6% 4 5% 7% 31%	1670
	11th to 20th	Day	21% 10% 3 6% 5% 4 5% 3 5% 6% 31%	1680
	21st to end	Day	18% 13% 4 9% 4 4 5% 4 6% 6% 28%	1680
December	1st to 10th	Day	15% 12% 3 7% 4 5% 5% 3 5% 5% 35%	2530
	11th to 20th	Day	16% 10% 3 9% 6% 5% 5% 4 4 5% 31%	2688
	21st to end	Day	14% 13% 5% 8% 5% 5% 4 3 4 4 35%	3553
January	1st to 10th	Night	14% 16% 4 9% 5% 5% 4 4 5% 6% 27%	8831
	11th to 20th	Night	14% 14% 6% 10% 6% 5% 4 4 5% 6% 26%	8737
	21st to end	Night	4 9% 4 9% 4 5% 5% 5% 6% 7% 43%	8741
February	1st to 10th	Night	10% 13% 4 7% 5% 5% 5% 4 6% 8% 34%	2730
	11th to 20th	Night	14% 15% 4 8% 5% 5% 5% 3 5% 5% 31%	2663
	21st to end	Night	12% 13% 4 7% 5% 4 5% 5% 5% 5% 35%	2202
March	1st to 10th	Night	19% 13% 4 8% 5% 4 5% 3 4 5% 30%	5186
	11th to 20th	Night	21% 14% 4 8% 5% 5% 4 4 4 5% 25%	5089
	21st to end	Night	26% 12% 4 8% 4 4 3 3 4 6% 27%	5587
April	1st to 10th	Night	24% 12% 3 7% 4 4 4 3 4 5% 30%	2121
	11th to 20th	Night	22% 9% 3 7% 4 4 4 3 4 5% 33%	1868
	21st to end	Night	23% 12% 3 6% 4 3 3 3 4 6% 33%	1890
May	1st to 10th	Night	22% 11% 3 8% 5% 5% 4 3 5% 6% 29%	5041
	11th to 20th	Night	22% 8% 3 7% 4 4 4 3 5% 6% 34%	4670
	21st to end	Night	20% 9% 3 8% 5% 4 5% 3 4 6% 34%	4734
June	1st to 10th	Night	22% 10% 2 6% 4 3 6% 4 6% 6% 32%	1470
	11th to 20th	Night	19% 6% 2 5% 4 4 5% 5% 6% 6% 36%	1470
	21st to end	Night	22% 8% 3 8% 6% 6% 4 4 4 7% 29%	1470
July	1st to 10th	Night	13% 7% 3 7% 5% 5% 5% 4 6% 7% 37%	4110
	11th to 20th	Night	11% 5% 2 6% 4 5% 5% 5% 8% 8% 40%	4110
	21st to end	Night	8% 5% 2 7% 4 5% 6% 4 7% 9% 44%	4856
August	1st to 10th	Night	15% 7% 3 8% 5% 6% 6% 4 6% 6% 33%	3005
	11th to 20th	Night	13% 7% 2 7% 5% 4 5% 5% 7% 8% 38%	2909
	21st to end	Night	13% 5% 2 6% 4 4 4 3 5% 7% 47%	3223
September	1st to 10th	Night	17% 5% 2 4 3 3 4 4 5% 7% 46%	1995
	11th to 20th	Night	14% 5% 2 6% 3 3 3 3 5% 8% 49%	2158
	21st to end	Night	17% 4 2 6% 3 4 3 3 5% 6% 46%	2205
October	1st to 10th	Night	19% 5% 2 6% 4 4 4 3 4 6% 43%	2400
	11th to 20th	Night	18% 8% 3 7% 5% 4 5% 3 5% 6% 39%	2400
	21st to end	Night	21% 9% 3 6% 3 4 4 3 6% 7% 35%	2765
November	1st to 10th	Night	20% 9% 3 7% 4 4 4 4 5% 6% 34%	2848
	11th to 20th	Night	20% 11% 4 8% 5% 4 4 3 5% 5% 30%	2940
	21st to end	Night	22% 11% 3 6% 4 5% 4 4 5% 6% 29%	2940
December	1st to 10th	Night	14% 10% 3 7% 5% 4 4 3 5% 6% 39%	4874
	11th to 20th	Night	17% 12% 3 7% 5% 5% 4 3 5% 5% 33%	5741
	21st to end	Night	17% 12% 4 10% 4 4 4 3 4 5% 32%	7667

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	63% 5% 11% 13% 9%	4094
	11th to 20th	Day	63% 5% 10% 13% 9%	4184
	21st to end	Day	44% 5% 11% 22% 17% 1	5438
February	1st to 10th	Day	51% 5% 12% 19% 11% 2	1890
	11th to 20th	Day	57% 5% 10% 18% 10% 1	1851
	21st to end	Day	50% 4 9% 23% 12% 3	1599
March	1st to 10th	Day	56% 5% 10% 16% 12% 1	4877
	11th to 20th	Day	60% 6% 12% 13% 7% 3	5090
	21st to end	Day	60% 2 5% 19% 13% 2	5587
April	1st to 10th	Day	56% 3 9% 17% 13% 2	2495
	11th to 20th	Day	49% 4 11% 21% 13% 2	2702
	21st to end	Day	56% 4 9% 15% 12% 4	2730
May	1st to 10th	Day	63% 3 9% 15% 10%	7879
	11th to 20th	Day	53% 4 13% 21% 9% 1	8224
	21st to end	Day	54% 5% 9% 19% 13% 1	9529
June	1st to 10th	Day	53% 5% 11% 20% 11%	3150
	11th to 20th	Day	49% 5% 13% 20% 11% 2	3150
	21st to end	Day	58% 6% 11% 16% 8% 1	3150
July	1st to 10th	Day	47% 2 16% 22% 12%	8805
	11th to 20th	Day	46% 3 15% 29% 7% 1	8799
	21st to end	Day	40% 3 18% 30% 8%	8974
August	1st to 10th	Day	47% 5% 18% 21% 10%	4352
	11th to 20th	Day	46% 5% 19% 21% 8%	4266
	21st to end	Day	41% 4 15% 24% 15% 1	4675
September	1st to 10th	Day	41% 5% 14% 26% 13%	2404
	11th to 20th	Day	41% 5% 13% 26% 14% 1	2239
	21st to end	Day	43% 6% 11% 27% 12% 1	2194
October	1st to 10th	Day	46% 3 14% 27% 9% 1	3260
	11th to 20th	Day	53% 4 11% 24% 8%	3240
	21st to end	Day	45% 4 15% 22% 14% 1	3321
November	1st to 10th	Day	53% 6% 10% 21% 8% 1	1670
	11th to 20th	Day	55% 7% 13% 15% 9% 1	1680
	21st to end	Day	57% 9% 13% 16% 5%	1680
December	1st to 10th	Day	55% 5% 11% 20% 9%	2530
	11th to 20th	Day	57% 4 11% 17% 10% 1	2688
	21st to end	Day	54% 5% 11% 18% 9% 2	3553
January	1st to 10th	Night	58% 6% 12% 19% 5%	8831
	11th to 20th	Night	61% 5% 10% 16% 8%	8786
	21st to end	Night	42% 4 12% 24% 18% 1	8741
February	1st to 10th	Night	50% 5% 11% 18% 13% 2	2730
	11th to 20th	Night	55% 5% 10% 18% 11% 1	2666
	21st to end	Night	51% 4 9% 20% 13% 2	2202
March	1st to 10th	Night	58% 3 8% 15% 14% 1	5195
	11th to 20th	Night	61% 6% 10% 14% 9% 1	5090
	21st to end	Night	61% 3 5% 15% 14% 2	5587
April	1st to 10th	Night	57% 4 7% 16% 14% 2	2121
	11th to 20th	Night	53% 5% 8% 19% 13% 2	1868
	21st to end	Night	54% 5% 7% 17% 15% 3	1890
May	1st to 10th	Night	57% 5% 9% 17% 12% 1	5047
	11th to 20th	Night	51% 4 9% 23% 11% 1	4671
	21st to end	Night	52% 5% 10% 18% 15%	4735
June	1st to 10th	Night	52% 6% 10% 20% 12% 1	1470
	11th to 20th	Night	46% 6% 12% 23% 11% 2	1470
	21st to end	Night	57% 5% 12% 16% 9% 1	1470
July	1st to 10th	Night	48% 3 15% 24% 10%	4075
	11th to 20th	Night	42% 3 18% 33% 4	4068
	21st to end	Night	38% 5% 20% 29% 8%	4747
August	1st to 10th	Night	52% 6% 13% 22% 8%	2993
	11th to 20th	Night	44% 5% 20% 24% 6%	2936
	21st to end	Night	38% 4 18% 25% 15%	3223
September	1st to 10th	Night	38% 6% 12% 32% 11% 1	1995
	11th to 20th	Night	35% 5% 15% 31% 13% 1	2158
	21st to end	Night	39% 6% 12% 29% 14% 1	2205
October	1st to 10th	Night	49% 3 10% 28% 9% 1	3920
	11th to 20th	Night	47% 4 10% 30% 9%	3899
	21st to end	Night	45% 4 17% 22% 11%	4465
November	1st to 10th	Night	51% 7% 13% 20% 8% 1	2848
	11th to 20th	Night	56% 7% 11% 17% 8% 1	2940
	21st to end	Night	57% 9% 13% 15% 5% 1	2940
December	1st to 10th	Night	48% 5% 12% 25% 9%	4874
	11th to 20th	Night	54% 6% 9% 21% 10% 1	5742
	21st to end	Night	55% 5% 13% 19% 8% 1	7667

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	32% 18% 30% 15% 4 1	220
	11th to 20th	Day	36% 18% 23% 14% 8% 2	220
	21st to end	Day	21% 18% 36% 21% 4 1	349
February	1st to 10th	Day	24% 24% 28% 15% 6% 3	430
	11th to 20th	Day	25% 26% 29% 15% 4 1	426
	21st to end	Day	24% 21% 35% 16% 4 1	377
March	1st to 10th	Day	31% 18% 34% 14% 2 1	540
	11th to 20th	Day	30% 20% 28% 15% 6% 2	540
	21st to end	Day	31% 21% 29% 12% 5% 1	594
April	1st to 10th	Day	37% 20% 28% 11% 3 1	540
	11th to 20th	Day	31% 20% 28% 15% 5% 1	532
	21st to end	Day	35% 16% 26% 16% 5% 2	540
May	1st to 10th	Day	33% 17% 28% 15% 6% 1	617
	11th to 20th	Day	28% 17% 27% 17% 9% 2	774
	21st to end	Day	31% 16% 30% 17% 7%	845
June	1st to 10th	Day	30% 13% 29% 20% 7% 2	780
	11th to 20th	Day	26% 15% 29% 20% 9% 2	780
	21st to end	Day	27% 14% 28% 21% 8% 2	780
July	1st to 10th	Day	19% 14% 33% 22% 11% 1	770
	11th to 20th	Day	14% 12% 38% 27% 8% 1	768
	21st to end	Day	20% 10% 31% 24% 11% 3	792
August	1st to 10th	Day	17% 13% 33% 25% 11% 2	566
	11th to 20th	Day	19% 10% 29% 28% 13% 2	535
	21st to end	Day	19% 11% 31% 24% 12% 3	583
September	1st to 10th	Day	17% 17% 32% 22% 9% 3	530
	11th to 20th	Day	23% 16% 28% 21% 9% 3	530
	21st to end	Day	24% 17% 31% 16% 8% 4	526
October	1st to 10th	Day	18% 19% 28% 21% 10% 4	420
	11th to 20th	Day	29% 18% 26% 15% 9% 3	420
	21st to end	Day	33% 22% 24% 15% 6% 1	462
November	1st to 10th	Day	31% 21% 29% 13% 4 1	425
	11th to 20th	Day	34% 18% 28% 13% 5% 1	430
	21st to end	Day	34% 20% 32% 12% 3	430
December	1st to 10th	Day	33% 16% 32% 14% 3 1	335
	11th to 20th	Day	32% 26% 28% 11% 2	220
	21st to end	Day	33% 19% 30% 15% 3	242
January	1st to 10th	Night	27% 19% 32% 18% 4	950
	11th to 20th	Night	27% 18% 33% 16% 5%	933
	21st to end	Night	19% 21% 36% 19% 4	924
February	1st to 10th	Night	20% 21% 32% 20% 6% 1	840
	11th to 20th	Night	29% 19% 31% 16% 4 1	823
	21st to end	Night	21% 17% 38% 18% 5%	692
March	1st to 10th	Night	27% 19% 33% 18% 3	840
	11th to 20th	Night	27% 15% 32% 19% 6% 1	840
	21st to end	Night	24% 18% 32% 20% 5% 1	924
April	1st to 10th	Night	32% 17% 30% 18% 3	688
	11th to 20th	Night	29% 14% 31% 18% 7%	624
	21st to end	Night	31% 13% 25% 23% 6% 1	630
May	1st to 10th	Night	28% 12% 28% 24% 7%	630
	11th to 20th	Night	25% 14% 30% 22% 9%	622
	21st to end	Night	23% 16% 32% 24% 5%	542
June	1st to 10th	Night	28% 8% 27% 30% 6%	420
	11th to 20th	Night	22% 10% 28% 29% 9% 1	420
	21st to end	Night	25% 9% 29% 28% 9% 1	420
July	1st to 10th	Night	19% 9% 35% 27% 10%	410
	11th to 20th	Night	12% 7% 39% 34% 7% 1	408
	21st to end	Night	16% 9% 32% 31% 12%	539
August	1st to 10th	Night	18% 7% 30% 34% 11%	628
	11th to 20th	Night	16% 9% 26% 37% 13%	605
	21st to end	Night	15% 10% 31% 31% 13% 1	660
September	1st to 10th	Night	19% 13% 33% 27% 8%	600
	11th to 20th	Night	20% 11% 30% 28% 11% 1	758
	21st to end	Night	21% 13% 32% 25% 10%	800
October	1st to 10th	Night	22% 16% 30% 23% 10% 1	800
	11th to 20th	Night	25% 16% 33% 19% 8%	800
	21st to end	Night	29% 20% 26% 20% 4	880
November	1st to 10th	Night	31% 19% 29% 17% 5%	916
	11th to 20th	Night	31% 19% 29% 14% 5% 2	950
	21st to end	Night	31% 18% 30% 16% 4	950
December	1st to 10th	Night	29% 18% 33% 16% 4	950
	11th to 20th	Night	32% 24% 29% 11% 4	950
	21st to end	Night	30% 21% 29% 16% 2 1	1045

Page generated at 2026-08-12 04:37:19. Version ac07

Copyright © 2026 Attilla Danko.