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 2024-10-24.

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	17% 9% 3 7% 5% 5% 5% 4 6% 7% 33%	101644
	Night	17% 10% 3 7% 5% 4 4 4 5% 6% 34%	97213
Transparency	Day	50% 6% 13% 20% 10% 1	101387
	Night	50% 7% 12% 20% 10% 1	97091
Seeing	Day	26% 17% 30% 18% 7% 2	16441
	Night	25% 16% 31% 21% 6% 1	24038

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	13% 11% 3 10% 6% 6% 5% 4 4 6% 32%	2207
	11th to 20th	Day	12% 11% 4 8% 10% 7% 6% 4 5% 7% 25%	2245
	21st to end	Day	6% 8% 3 9% 5% 5% 5% 5% 6% 7% 42%	2933
February	1st to 10th	Day	10% 13% 4 8% 5% 5% 5% 5% 6% 6% 32%	1710
	11th to 20th	Day	13% 14% 4 10% 6% 5% 5% 4 5% 6% 28%	1663
	21st to end	Day	10% 12% 4 9% 5% 5% 5% 4 6% 7% 34%	1451
March	1st to 10th	Day	17% 13% 4 6% 4 4 6% 4 4 6% 33%	3323
	11th to 20th	Day	16% 17% 5% 11% 6% 5% 4 3 4 5% 23%	3480
	21st to end	Day	24% 11% 3 7% 5% 4 4 3 4 5% 30%	3816
April	1st to 10th	Day	20% 12% 4 8% 6% 4 3 3 5% 6% 30%	2257
	11th to 20th	Day	19% 9% 2 6% 4 3 5% 3 5% 6% 37%	2442
	21st to end	Day	24% 10% 4 7% 4 4 3 3 5% 5% 30%	2470
May	1st to 10th	Day	20% 14% 4 8% 6% 5% 4 3 5% 6% 26%	4224
	11th to 20th	Day	19% 9% 3 7% 5% 4 4 3 6% 7% 33%	4398
	21st to end	Day	19% 8% 3 8% 6% 5% 5% 4 6% 7% 28%	5081
June	1st to 10th	Day	24% 8% 3 6% 4 4 4 3 6% 7% 31%	2850
	11th to 20th	Day	18% 7% 3 5% 5% 5% 5% 4 6% 7% 36%	2850
	21st to end	Day	24% 8% 3 7% 6% 6% 5% 4 6% 6% 26%	2850
July	1st to 10th	Day	14% 6% 3 8% 6% 6% 6% 5% 7% 8% 33%	4760
	11th to 20th	Day	12% 6% 2 7% 5% 6% 6% 5% 7% 8% 34%	4760
	21st to end	Day	12% 6% 2 6% 4 5% 5% 4 7% 9% 41%	4919
August	1st to 10th	Day	14% 7% 2 7% 5% 6% 6% 5% 7% 8% 33%	4105
	11th to 20th	Day	14% 5% 2 7% 6% 6% 6% 5% 7% 8% 34%	4045
	21st to end	Day	15% 5% 2 5% 4 4 4 4 5% 7% 44%	4532
September	1st to 10th	Day	15% 5% 2 7% 4 5% 4 3 6% 7% 42%	2284
	11th to 20th	Day	17% 5% 3 5% 4 4 4 3 4 5% 46%	2127
	21st to end	Day	18% 5% 2 6% 4 4 4 4 6% 7% 40%	2085
October	1st to 10th	Day	15% 6% 3 7% 5% 5% 4 3 5% 6% 42%	1900
	11th to 20th	Day	20% 8% 3 7% 4 4 5% 4 5% 6% 34%	1900
	21st to end	Day	24% 8% 3 6% 4 4 4 3 5% 6% 34%	1895
November	1st to 10th	Day	18% 9% 3 7% 5% 6% 6% 4 5% 7% 32%	1508
	11th to 20th	Day	20% 10% 3 7% 5% 5% 6% 4 5% 6% 31%	1520
	21st to end	Day	17% 13% 4 9% 5% 4 5% 4 6% 7% 28%	1520
December	1st to 10th	Day	21% 12% 3 7% 4 5% 5% 4 5% 6% 29%	1435
	11th to 20th	Day	16% 12% 4 10% 6% 6% 6% 4 5% 5% 26%	1668
	21st to end	Day	17% 12% 4 7% 5% 5% 4 3 4 4 35%	2431
January	1st to 10th	Night	10% 10% 4 9% 5% 6% 5% 5% 7% 8% 32%	4748
	11th to 20th	Night	16% 11% 4 9% 6% 5% 5% 4 5% 6% 29%	4722
	21st to end	Night	8% 12% 3 7% 4 4 4 4 6% 7% 40%	4721
February	1st to 10th	Night	10% 14% 4 6% 4 5% 5% 4 6% 8% 34%	2470
	11th to 20th	Night	14% 15% 4 8% 6% 5% 5% 3 5% 5% 30%	2403
	21st to end	Night	12% 14% 4 6% 6% 4 5% 5% 5% 5% 33%	1998
March	1st to 10th	Night	15% 12% 4 9% 5% 4 6% 3 5% 6% 31%	3516
	11th to 20th	Night	24% 16% 4 7% 5% 5% 5% 4 4 4 22%	3479
	21st to end	Night	26% 11% 3 7% 4 4 3 3 5% 7% 27%	3816
April	1st to 10th	Night	24% 11% 3 7% 4 4 3 3 4 5% 31%	1919
	11th to 20th	Night	22% 8% 3 7% 5% 4 4 4 5% 5% 34%	1688
	21st to end	Night	24% 12% 3 6% 4 3 3 3 4 6% 34%	1710
May	1st to 10th	Night	22% 10% 3 8% 5% 5% 4 3 5% 6% 29%	2718
	11th to 20th	Night	18% 7% 3 6% 4 4 4 4 6% 7% 36%	2506
	21st to end	Night	16% 9% 3 7% 6% 5% 6% 4 5% 8% 30%	2532
June	1st to 10th	Night	23% 10% 2 5% 4 3 6% 3 6% 5% 32%	1330
	11th to 20th	Night	18% 6% 2 5% 4 4 5% 5% 6% 7% 37%	1330
	21st to end	Night	23% 7% 3 7% 6% 6% 4 4 4 7% 30%	1330
July	1st to 10th	Night	12% 7% 3 7% 5% 5% 5% 4 6% 6% 40%	2210
	11th to 20th	Night	14% 6% 3 7% 4 5% 5% 5% 7% 7% 37%	2210
	21st to end	Night	10% 5% 2 6% 4 4 5% 4 6% 8% 46%	2604
August	1st to 10th	Night	16% 7% 3 8% 6% 6% 6% 4 6% 6% 31%	2825
	11th to 20th	Night	13% 7% 2 7% 5% 4 5% 5% 7% 8% 37%	2782
	21st to end	Night	13% 5% 2 6% 4 4 4 3 5% 7% 47%	3124
September	1st to 10th	Night	17% 5% 2 4 3 3 4 4 5% 7% 45%	1895
	11th to 20th	Night	14% 6% 2 6% 3 2 3 3 5% 8% 48%	2050
	21st to end	Night	17% 4 2 6% 3 4 3 3 5% 7% 46%	2095
October	1st to 10th	Night	20% 5% 2 6% 4 4 4 3 4 6% 42%	2280
	11th to 20th	Night	18% 8% 3 7% 5% 4 5% 3 5% 6% 39%	2280
	21st to end	Night	22% 9% 2 5% 4 4 4 3 6% 7% 35%	2525
November	1st to 10th	Night	20% 8% 3 7% 4 4 4 4 5% 6% 35%	2570
	11th to 20th	Night	19% 11% 4 7% 5% 4 4 3 5% 6% 31%	2660
	21st to end	Night	20% 11% 3 6% 5% 5% 5% 4 5% 7% 29%	2660
December	1st to 10th	Night	21% 11% 3 7% 4 4 4 3 5% 6% 31%	2740
	11th to 20th	Night	19% 13% 3 8% 5% 6% 5% 4 5% 5% 26%	3531
	21st to end	Night	18% 12% 4 8% 5% 4 4 3 4 5% 33%	5236

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	54% 8% 12% 15% 10% 1	2208
	11th to 20th	Day	56% 10% 8% 15% 11%	2245
	21st to end	Day	40% 9% 13% 24% 13% 1	2933
February	1st to 10th	Day	50% 6% 12% 19% 11% 2	1710
	11th to 20th	Day	58% 5% 9% 17% 9% 1	1671
	21st to end	Day	50% 5% 9% 23% 11% 3	1451
March	1st to 10th	Day	51% 6% 13% 21% 8% 1	3327
	11th to 20th	Day	62% 7% 9% 14% 6% 2	3480
	21st to end	Day	57% 4 8% 18% 11% 2	3816
April	1st to 10th	Day	56% 3 9% 17% 12% 2	2257
	11th to 20th	Day	48% 5% 12% 21% 14% 2	2442
	21st to end	Day	56% 5% 8% 15% 12% 4	2470
May	1st to 10th	Day	59% 5% 9% 18% 8% 1	4238
	11th to 20th	Day	49% 7% 15% 21% 8% 1	4402
	21st to end	Day	51% 8% 11% 19% 10%	5081
June	1st to 10th	Day	53% 6% 11% 19% 11%	2850
	11th to 20th	Day	47% 6% 13% 21% 11% 2	2850
	21st to end	Day	58% 6% 11% 16% 8%	2850
July	1st to 10th	Day	49% 4 16% 20% 10%	4685
	11th to 20th	Day	47% 5% 15% 26% 7%	4679
	21st to end	Day	40% 6% 21% 23% 10%	4761
August	1st to 10th	Day	48% 5% 17% 20% 9%	4092
	11th to 20th	Day	47% 5% 19% 21% 8%	4084
	21st to end	Day	41% 4 15% 24% 15% 1	4532
September	1st to 10th	Day	42% 6% 14% 25% 13%	2284
	11th to 20th	Day	41% 5% 13% 26% 14% 1	2127
	21st to end	Day	44% 6% 11% 26% 12% 1	2085
October	1st to 10th	Day	44% 5% 13% 27% 11% 1	1900
	11th to 20th	Day	50% 6% 14% 22% 8%	1900
	21st to end	Day	52% 5% 12% 19% 10% 1	1895
November	1st to 10th	Day	52% 7% 11% 20% 9% 1	1508
	11th to 20th	Day	54% 8% 13% 15% 9% 1	1520
	21st to end	Day	57% 10% 13% 16% 5%	1520
December	1st to 10th	Day	58% 9% 11% 16% 7%	1435
	11th to 20th	Day	61% 7% 10% 14% 8% 1	1668
	21st to end	Day	53% 7% 13% 15% 9% 3	2431
January	1st to 10th	Night	48% 11% 17% 18% 5%	4748
	11th to 20th	Night	54% 9% 10% 16% 10%	4722
	21st to end	Night	42% 7% 14% 23% 14% 1	4721
February	1st to 10th	Night	49% 6% 12% 18% 13% 2	2470
	11th to 20th	Night	55% 5% 9% 18% 11% 1	2406
	21st to end	Night	52% 5% 9% 20% 13% 2	1998
March	1st to 10th	Night	55% 5% 10% 20% 9% 1	3525
	11th to 20th	Night	63% 8% 7% 14% 7% 1	3480
	21st to end	Night	58% 4 7% 18% 12% 2	3816
April	1st to 10th	Night	56% 4 8% 16% 14% 3	1919
	11th to 20th	Night	51% 6% 8% 18% 14% 2	1688
	21st to end	Night	53% 5% 7% 17% 14% 3	1710
May	1st to 10th	Night	55% 7% 10% 16% 11% 1	2724
	11th to 20th	Night	44% 8% 14% 25% 8% 1	2507
	21st to end	Night	49% 10% 13% 20% 8% 1	2533
June	1st to 10th	Night	53% 7% 10% 19% 11% 1	1330
	11th to 20th	Night	44% 7% 13% 24% 11% 2	1330
	21st to end	Night	56% 6% 12% 17% 8% 1	1330
July	1st to 10th	Night	44% 5% 18% 22% 12%	2175
	11th to 20th	Night	46% 5% 15% 28% 6%	2168
	21st to end	Night	36% 8% 20% 26% 10%	2522
August	1st to 10th	Night	53% 6% 13% 21% 7%	2813
	11th to 20th	Night	45% 6% 20% 23% 6%	2809
	21st to end	Night	38% 4 17% 25% 15%	3124
September	1st to 10th	Night	39% 7% 12% 30% 11% 1	1895
	11th to 20th	Night	35% 5% 15% 30% 13% 1	2050
	21st to end	Night	39% 6% 12% 29% 13% 1	2095
October	1st to 10th	Night	45% 6% 11% 25% 12% 1	2280
	11th to 20th	Night	48% 6% 12% 25% 8%	2280
	21st to end	Night	50% 7% 14% 20% 9% 1	2525
November	1st to 10th	Night	50% 8% 13% 20% 9% 1	2570
	11th to 20th	Night	54% 8% 12% 17% 8% 1	2660
	21st to end	Night	56% 10% 14% 15% 5% 1	2660
December	1st to 10th	Night	54% 9% 12% 18% 6%	2740
	11th to 20th	Night	60% 9% 9% 16% 6%	3532
	21st to end	Night	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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	31% 18% 31% 16% 3 1	180
	11th to 20th	Day	36% 19% 26% 12% 6% 1	180
	21st to end	Day	21% 18% 34% 21% 5% 1	294
February	1st to 10th	Day	25% 26% 26% 15% 6% 2	370
	11th to 20th	Day	25% 28% 28% 16% 3 1	366
	21st to end	Day	23% 22% 35% 16% 4 1	325
March	1st to 10th	Day	30% 17% 35% 14% 3 1	460
	11th to 20th	Day	29% 18% 28% 16% 7% 2	460
	21st to end	Day	31% 23% 28% 11% 6% 1	506
April	1st to 10th	Day	36% 19% 28% 12% 3 1	460
	11th to 20th	Day	29% 20% 29% 16% 5% 1	452
	21st to end	Day	35% 18% 25% 14% 4 2	460
May	1st to 10th	Day	32% 16% 28% 17% 6% 1	529
	11th to 20th	Day	28% 16% 27% 17% 11% 2	674
	21st to end	Day	29% 17% 31% 16% 6%	735
June	1st to 10th	Day	32% 13% 28% 19% 7% 2	680
	11th to 20th	Day	25% 16% 28% 21% 8% 2	680
	21st to end	Day	27% 15% 29% 21% 7% 1	680
July	1st to 10th	Day	19% 14% 32% 23% 10% 1	670
	11th to 20th	Day	14% 12% 36% 28% 8% 2	668
	21st to end	Day	20% 10% 31% 25% 11% 2	688
August	1st to 10th	Day	17% 14% 34% 24% 10% 1	486
	11th to 20th	Day	19% 10% 30% 28% 12% 1	479
	21st to end	Day	20% 10% 29% 26% 12% 3	539
September	1st to 10th	Day	17% 17% 33% 23% 8% 2	490
	11th to 20th	Day	23% 17% 29% 20% 8% 3	490
	21st to end	Day	25% 17% 30% 16% 8% 4	487
October	1st to 10th	Day	19% 19% 27% 21% 11% 4	390
	11th to 20th	Day	30% 19% 27% 14% 8% 2	390
	21st to end	Day	34% 23% 22% 15% 6% 1	405
November	1st to 10th	Day	30% 22% 28% 14% 5% 1	365
	11th to 20th	Day	32% 19% 29% 14% 5% 1	370
	21st to end	Day	32% 21% 31% 12% 3 1	370
December	1st to 10th	Day	35% 15% 30% 15% 4 1	285
	11th to 20th	Day	32% 28% 27% 12% 2 1	180
	21st to end	Day	35% 20% 29% 13% 2	198
January	1st to 10th	Night	25% 20% 33% 18% 4	850
	11th to 20th	Night	28% 19% 34% 15% 4	837
	21st to end	Night	20% 21% 35% 19% 4	836
February	1st to 10th	Night	21% 22% 32% 19% 5% 1	760
	11th to 20th	Night	29% 20% 31% 15% 4 1	743
	21st to end	Night	22% 18% 37% 17% 6%	628
March	1st to 10th	Night	26% 19% 33% 19% 3	760
	11th to 20th	Night	26% 15% 34% 18% 7% 1	760
	21st to end	Night	25% 18% 32% 19% 5% 1	836
April	1st to 10th	Night	32% 16% 30% 18% 4	622
	11th to 20th	Night	28% 15% 31% 18% 7%	564
	21st to end	Night	32% 14% 25% 22% 6% 1	570
May	1st to 10th	Night	27% 12% 28% 25% 7%	570
	11th to 20th	Night	24% 13% 30% 23% 9%	562
	21st to end	Night	22% 16% 34% 24% 5%	490
June	1st to 10th	Night	29% 9% 26% 29% 7%	380
	11th to 20th	Night	20% 10% 29% 31% 9% 1	380
	21st to end	Night	25% 9% 29% 28% 8% 1	380
July	1st to 10th	Night	18% 9% 35% 26% 10% 1	370
	11th to 20th	Night	13% 7% 37% 36% 7% 1	368
	21st to end	Night	16% 9% 31% 32% 12%	487
August	1st to 10th	Night	18% 7% 32% 33% 10%	568
	11th to 20th	Night	16% 9% 26% 36% 12%	562
	21st to end	Night	15% 9% 31% 31% 14% 1	627
September	1st to 10th	Night	19% 14% 33% 26% 8%	570
	11th to 20th	Night	20% 11% 30% 27% 11% 1	720
	21st to end	Night	21% 13% 32% 25% 10%	760
October	1st to 10th	Night	23% 15% 29% 22% 10% 1	760
	11th to 20th	Night	24% 17% 33% 18% 7%	760
	21st to end	Night	30% 20% 27% 19% 4	805
November	1st to 10th	Night	30% 19% 28% 18% 5%	818
	11th to 20th	Night	29% 20% 30% 14% 5% 2	850
	21st to end	Night	30% 19% 30% 17% 4	850
December	1st to 10th	Night	30% 19% 32% 14% 4	850
	11th to 20th	Night	32% 24% 29% 10% 4	850
	21st to end	Night	31% 21% 29% 16% 2 1	935

Page generated at 2024-10-21 03:19:59. Version ac07

Copyright © 2024 Attilla Danko.