Hackbart Road Hill
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hackbart Road Hill clear sky chart from 2005-11-06 to 2024-11-03.

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	14% 11% 4 9% 5% 5% 5% 4 6% 7% 30%	102058
	Night	14% 11% 4 9% 6% 5% 4 4 5% 6% 31%	96912
Transparency	Day	52% 7% 12% 19% 10% 1	101820
	Night	52% 7% 12% 18% 10% 1	96770
Seeing	Day	19% 12% 29% 23% 12% 5%	14967
	Night	19% 11% 30% 28% 11% 1	23897

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	15% 19% 9% 14% 6% 4 4 3 3 4 20%	2590
	11th to 20th	Day	11% 20% 10% 20% 8% 7% 6% 3 3 3 8%	2840
	21st to end	Day	20% 20% 9% 14% 6% 5% 5% 3 3 4 10%	3124
February	1st to 10th	Day	15% 20% 5% 13% 10% 7% 5% 4 3 4 15%	1710
	11th to 20th	Day	12% 14% 9% 15% 9% 5% 5% 3 5% 6% 17%	1663
	21st to end	Day	16% 16% 7% 12% 7% 5% 4 3 5% 4 21%	1527
March	1st to 10th	Day	19% 15% 5% 10% 6% 4 4 3 3 4 26%	3385
	11th to 20th	Day	11% 15% 7% 11% 5% 5% 5% 4 5% 6% 27%	3480
	21st to end	Day	15% 13% 4 11% 5% 5% 5% 3 5% 5% 29%	3815
April	1st to 10th	Day	16% 16% 4 8% 4 3 4 4 5% 7% 27%	2189
	11th to 20th	Day	19% 11% 2 7% 5% 3 4 3 5% 6% 35%	2400
	21st to end	Day	20% 11% 4 8% 4 4 3 4 4 6% 32%	2470
May	1st to 10th	Day	18% 9% 3 7% 4 5% 5% 3 6% 8% 33%	4108
	11th to 20th	Day	16% 10% 3 8% 5% 4 4 4 6% 8% 30%	4204
	21st to end	Day	13% 5% 2 6% 4 4 4 4 6% 7% 45%	4837
June	1st to 10th	Day	14% 7% 2 6% 5% 5% 5% 4 6% 9% 36%	2660
	11th to 20th	Day	11% 6% 2 7% 5% 5% 6% 4 6% 9% 39%	2817
	21st to end	Day	13% 6% 3 7% 6% 4 5% 4 6% 8% 38%	2850
July	1st to 10th	Day	10% 5% 2 6% 5% 5% 6% 5% 8% 10% 37%	4760
	11th to 20th	Day	10% 6% 2 5% 5% 5% 5% 4 8% 9% 41%	4329
	21st to end	Day	9% 6% 2 6% 5% 5% 5% 5% 7% 9% 41%	4466
August	1st to 10th	Day	14% 7% 3 6% 4 5% 5% 4 7% 9% 35%	4104
	11th to 20th	Day	10% 8% 3 8% 5% 5% 6% 5% 7% 10% 33%	4044
	21st to end	Day	8% 6% 2 7% 5% 6% 6% 5% 7% 9% 39%	4445
September	1st to 10th	Day	11% 6% 3 7% 6% 4 6% 5% 6% 9% 38%	2271
	11th to 20th	Day	10% 7% 2 7% 4 4 5% 5% 6% 8% 42%	2090
	21st to end	Day	16% 8% 2 6% 5% 6% 5% 4 6% 7% 34%	2090
October	1st to 10th	Day	17% 9% 3 8% 5% 5% 5% 4 4 6% 33%	1914
	11th to 20th	Day	20% 11% 4 8% 5% 5% 4 3 5% 7% 28%	1900
	21st to end	Day	23% 14% 4 8% 5% 5% 6% 4 6% 5% 20%	2071
November	1st to 10th	Day	14% 16% 3 10% 4 4 4 3 5% 7% 30%	1667
	11th to 20th	Day	14% 17% 4 10% 7% 5% 5% 4 6% 7% 22%	1520
	21st to end	Day	17% 18% 8% 11% 6% 4 4 4 5% 6% 16%	1520
December	1st to 10th	Day	14% 22% 8% 15% 8% 5% 3 4 4 5% 12%	1520
	11th to 20th	Day	17% 20% 7% 13% 7% 5% 6% 4 5% 3 14%	1906
	21st to end	Day	28% 21% 8% 15% 6% 4 4 2 3 3 7%	2772
January	1st to 10th	Night	16% 19% 8% 17% 7% 5% 5% 3 4 4 13%	4351
	11th to 20th	Night	13% 15% 8% 17% 10% 8% 5% 5% 6% 4 8%	4120
	21st to end	Night	20% 16% 10% 15% 7% 4 4 3 4 4 14%	4532
February	1st to 10th	Night	15% 17% 6% 11% 9% 7% 5% 4 4 5% 17%	2470
	11th to 20th	Night	13% 13% 5% 12% 8% 6% 6% 4 5% 7% 21%	2403
	21st to end	Night	16% 13% 4 13% 7% 6% 4 4 5% 6% 23%	1924
March	1st to 10th	Night	15% 11% 4 9% 6% 5% 4 4 5% 6% 32%	3453
	11th to 20th	Night	10% 10% 4 10% 5% 4 5% 4 6% 8% 34%	3479
	21st to end	Night	15% 9% 4 9% 5% 4 4 3 4 5% 37%	3817
April	1st to 10th	Night	19% 11% 3 8% 6% 4 4 4 5% 6% 31%	1990
	11th to 20th	Night	17% 10% 3 7% 5% 4 4 3 5% 7% 35%	1744
	21st to end	Night	15% 10% 4 8% 6% 5% 4 4 5% 7% 34%	1710
May	1st to 10th	Night	17% 7% 2 6% 4 3 4 3 5% 7% 42%	2833
	11th to 20th	Night	13% 9% 3 7% 6% 5% 4 4 5% 7% 36%	2686
	21st to end	Night	10% 4 2 4 4 3 4 3 6% 9% 50%	2738
June	1st to 10th	Night	11% 7% 2 6% 4 4 5% 4 5% 7% 43%	1520
	11th to 20th	Night	10% 5% 2 5% 4 6% 5% 4 6% 10% 42%	1358
	21st to end	Night	12% 6% 2 5% 3 5% 4 5% 6% 8% 45%	1330
July	1st to 10th	Night	5% 5% 2 5% 4 3 4 4 7% 9% 52%	2210
	11th to 20th	Night	9% 5% 2 5% 4 4 4 3 5% 8% 52%	2610
	21st to end	Night	6% 5% 2 7% 4 5% 5% 4 6% 8% 48%	3087
August	1st to 10th	Night	11% 7% 2 6% 4 4 4 3 6% 7% 45%	2825
	11th to 20th	Night	10% 8% 3 6% 4 4 5% 4 5% 9% 42%	2785
	21st to end	Night	9% 6% 2 5% 4 4 4 3 6% 7% 48%	3178
September	1st to 10th	Night	9% 6% 3 6% 5% 5% 5% 4 6% 7% 45%	1905
	11th to 20th	Night	10% 5% 2 4 3 3 3 3 5% 7% 53%	2090
	21st to end	Night	16% 8% 2 7% 4 4 5% 3 6% 7% 39%	2090
October	1st to 10th	Night	15% 8% 4 8% 5% 4 4 3 5% 6% 39%	2266
	11th to 20th	Night	18% 10% 3 7% 5% 5% 4 4 5% 7% 32%	2280
	21st to end	Night	22% 10% 3 9% 6% 5% 5% 4 6% 6% 26%	2522
November	1st to 10th	Night	14% 11% 4 8% 5% 5% 4 4 5% 7% 34%	2454
	11th to 20th	Night	15% 14% 5% 10% 6% 6% 5% 4 6% 7% 23%	2660
	21st to end	Night	18% 15% 6% 9% 6% 5% 4 4 5% 7% 20%	2660
December	1st to 10th	Night	17% 19% 8% 12% 6% 5% 4 4 5% 5% 14%	2660
	11th to 20th	Night	13% 20% 6% 14% 7% 5% 5% 4 5% 5% 17%	3288
	21st to end	Night	26% 22% 8% 12% 6% 4 4 2 3 4 8%	4884

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	68% 7% 9% 10% 6%	2591
	11th to 20th	Day	78% 9% 6% 4 3	2840
	21st to end	Day	78% 6% 8% 6% 3	3124
February	1st to 10th	Day	71% 7% 8% 11% 3 1	1710
	11th to 20th	Day	65% 7% 9% 13% 6% 1	1672
	21st to end	Day	64% 6% 12% 12% 6% 1	1527
March	1st to 10th	Day	61% 6% 10% 17% 6% 1	3388
	11th to 20th	Day	55% 8% 12% 17% 7% 1	3480
	21st to end	Day	54% 7% 12% 16% 10% 2	3815
April	1st to 10th	Day	55% 7% 11% 16% 10%	2189
	11th to 20th	Day	49% 6% 12% 20% 12% 1	2400
	21st to end	Day	53% 6% 11% 18% 11% 2	2470
May	1st to 10th	Day	46% 8% 14% 19% 12% 2	4120
	11th to 20th	Day	48% 10% 15% 20% 6% 1	4208
	21st to end	Day	36% 8% 12% 20% 19% 5%	4837
June	1st to 10th	Day	43% 8% 13% 21% 14% 1	2660
	11th to 20th	Day	40% 8% 12% 24% 15% 1	2817
	21st to end	Day	42% 7% 13% 24% 13%	2850
July	1st to 10th	Day	40% 5% 16% 22% 15% 2	4686
	11th to 20th	Day	37% 5% 12% 33% 12% 1	4252
	21st to end	Day	38% 6% 14% 23% 18% 1	4324
August	1st to 10th	Day	44% 6% 13% 24% 12% 1	4091
	11th to 20th	Day	45% 6% 16% 24% 9%	4083
	21st to end	Day	40% 6% 12% 31% 10% 1	4445
September	1st to 10th	Day	40% 9% 14% 24% 11% 1	2271
	11th to 20th	Day	36% 8% 14% 28% 14% 1	2090
	21st to end	Day	47% 7% 14% 23% 9% 1	2090
October	1st to 10th	Day	50% 7% 12% 16% 13% 1	1914
	11th to 20th	Day	56% 6% 13% 17% 8%	1900
	21st to end	Day	63% 7% 12% 13% 5%	2071
November	1st to 10th	Day	53% 7% 13% 19% 7% 1	1667
	11th to 20th	Day	58% 8% 14% 12% 7% 1	1520
	21st to end	Day	66% 8% 12% 10% 3	1520
December	1st to 10th	Day	74% 7% 8% 9% 2	1520
	11th to 20th	Day	71% 8% 9% 8% 3	1906
	21st to end	Day	82% 6% 6% 5% 1	2772
January	1st to 10th	Night	72% 8% 8% 8% 3	4351
	11th to 20th	Night	73% 12% 8% 5% 2	4120
	21st to end	Night	72% 7% 9% 8% 3 1	4532
February	1st to 10th	Night	67% 7% 10% 13% 3	2470
	11th to 20th	Night	60% 8% 12% 14% 6%	2405
	21st to end	Night	60% 6% 13% 14% 8%	1924
March	1st to 10th	Night	51% 7% 14% 21% 6% 1	3463
	11th to 20th	Night	44% 8% 16% 20% 10% 1	3480
	21st to end	Night	46% 7% 10% 21% 14% 2	3817
April	1st to 10th	Night	53% 5% 10% 17% 13% 1	1990
	11th to 20th	Night	47% 7% 9% 20% 15% 2	1744
	21st to end	Night	49% 6% 10% 18% 15% 3	1710
May	1st to 10th	Night	42% 7% 12% 19% 16% 5%	2840
	11th to 20th	Night	44% 9% 15% 20% 10% 2	2687
	21st to end	Night	30% 8% 14% 23% 22% 3	2739
June	1st to 10th	Night	38% 7% 11% 26% 17% 2	1520
	11th to 20th	Night	36% 7% 13% 25% 17% 2	1358
	21st to end	Night	36% 7% 14% 24% 17% 1	1330
July	1st to 10th	Night	29% 5% 15% 25% 20% 6%	2175
	11th to 20th	Night	31% 5% 12% 32% 19% 1	2564
	21st to end	Night	33% 7% 13% 27% 17% 2	2988
August	1st to 10th	Night	38% 5% 13% 26% 16% 2	2814
	11th to 20th	Night	39% 6% 16% 27% 12% 1	2812
	21st to end	Night	35% 5% 11% 33% 15% 1	3178
September	1st to 10th	Night	36% 8% 12% 27% 15% 2	1905
	11th to 20th	Night	31% 6% 13% 30% 20% 1	2090
	21st to end	Night	43% 7% 13% 25% 12%	2090
October	1st to 10th	Night	46% 6% 11% 21% 15% 1	2266
	11th to 20th	Night	51% 6% 14% 20% 9% 1	2280
	21st to end	Night	56% 8% 11% 17% 8%	2522
November	1st to 10th	Night	49% 7% 14% 20% 10% 1	2454
	11th to 20th	Night	57% 9% 12% 14% 6% 1	2660
	21st to end	Night	60% 9% 15% 11% 4 1	2660
December	1st to 10th	Night	71% 8% 11% 8% 2	2660
	11th to 20th	Night	68% 7% 11% 11% 3	3288
	21st to end	Night	80% 6% 8% 5% 1	4884

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	22% 22% 31% 16% 8% 1	202
	11th to 20th	Day	20% 18% 44% 14% 3 1	270
	21st to end	Day	26% 17% 32% 21% 4	297
February	1st to 10th	Day	24% 20% 40% 13% 3	270
	11th to 20th	Day	23% 21% 39% 16% 1	270
	21st to end	Day	28% 28% 29% 13% 1	225
March	1st to 10th	Day	25% 14% 37% 18% 6%	424
	11th to 20th	Day	22% 15% 36% 21% 6% 1	460
	21st to end	Day	25% 15% 34% 20% 5% 1	506
April	1st to 10th	Day	20% 20% 31% 20% 8% 1	460
	11th to 20th	Day	28% 15% 28% 15% 10% 4	452
	21st to end	Day	26% 12% 32% 20% 8% 2	460
May	1st to 10th	Day	21% 13% 27% 24% 11% 4	463
	11th to 20th	Day	20% 9% 28% 23% 15% 6%	487
	21st to end	Day	15% 6% 27% 28% 17% 7%	529
June	1st to 10th	Day	14% 10% 29% 29% 14% 4	490
	11th to 20th	Day	14% 9% 30% 29% 16% 3	647
	21st to end	Day	15% 8% 30% 32% 12% 3	680
July	1st to 10th	Day	8% 7% 25% 29% 22% 9%	671
	11th to 20th	Day	15% 7% 23% 27% 20% 9%	515
	21st to end	Day	11% 3 25% 33% 19% 9%	532
August	1st to 10th	Day	12% 5% 20% 28% 23% 13%	486
	11th to 20th	Day	13% 5% 18% 28% 21% 15%	479
	21st to end	Day	14% 7% 21% 30% 18% 11%	539
September	1st to 10th	Day	12% 8% 23% 26% 19% 12%	490
	11th to 20th	Day	10% 4 19% 26% 26% 14%	490
	21st to end	Day	17% 9% 27% 24% 15% 8%	490
October	1st to 10th	Day	20% 12% 28% 21% 14% 7%	490
	11th to 20th	Day	21% 16% 32% 22% 7% 2	490
	21st to end	Day	29% 17% 29% 21% 5% 1	520
November	1st to 10th	Day	21% 22% 28% 20% 8% 1	265
	11th to 20th	Day	24% 18% 32% 20% 4 2	180
	21st to end	Day	23% 18% 39% 17% 3	180
December	1st to 10th	Day	27% 23% 33% 13% 4	180
	11th to 20th	Day	26% 26% 31% 14% 3 1	180
	21st to end	Day	30% 19% 37% 13% 1	198
January	1st to 10th	Night	22% 19% 37% 16% 6% 1	760
	11th to 20th	Night	27% 18% 32% 20% 4	760
	21st to end	Night	20% 11% 39% 25% 6%	836
February	1st to 10th	Night	21% 17% 38% 22% 2	760
	11th to 20th	Night	21% 15% 36% 22% 5%	743
	21st to end	Night	23% 17% 36% 22% 3	628
March	1st to 10th	Night	17% 15% 39% 22% 7%	760
	11th to 20th	Night	17% 19% 36% 22% 6%	760
	21st to end	Night	21% 13% 32% 24% 8% 1	836
April	1st to 10th	Night	23% 14% 32% 26% 5%	760
	11th to 20th	Night	21% 14% 31% 23% 9% 1	620
	21st to end	Night	19% 12% 29% 33% 7% 1	570
May	1st to 10th	Night	16% 6% 32% 30% 13% 1	570
	11th to 20th	Night	19% 4 28% 36% 13% 1	487
	21st to end	Night	11% 4 28% 38% 18%	411
June	1st to 10th	Night	14% 4 29% 39% 14%	380
	11th to 20th	Night	12% 5% 31% 39% 13%	380
	21st to end	Night	14% 4 28% 40% 14%	380
July	1st to 10th	Night	5% 2 20% 52% 21% 1	370
	11th to 20th	Night	9% 4 24% 39% 22% 2	455
	21st to end	Night	9% 2 21% 45% 21% 1	624
August	1st to 10th	Night	11% 2 18% 41% 26% 2	567
	11th to 20th	Night	8% 3 18% 38% 29% 4	564
	21st to end	Night	12% 4 23% 33% 26% 3	655
September	1st to 10th	Night	11% 5% 23% 35% 21% 4	760
	11th to 20th	Night	12% 4 19% 33% 26% 5%	760
	21st to end	Night	18% 8% 22% 30% 18% 5%	760
October	1st to 10th	Night	19% 8% 27% 28% 16% 2	760
	11th to 20th	Night	21% 13% 27% 28% 9% 1	760
	21st to end	Night	26% 13% 30% 26% 6%	836
November	1st to 10th	Night	21% 11% 28% 29% 9% 1	749
	11th to 20th	Night	22% 14% 35% 20% 7% 1	760
	21st to end	Night	25% 14% 34% 23% 4	760
December	1st to 10th	Night	27% 18% 32% 18% 4	760
	11th to 20th	Night	21% 21% 36% 18% 4	760
	21st to end	Night	29% 17% 34% 18% 3	836

Page generated at 2024-10-31 03:39:22. Version ac07

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