Heaven's Gate
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Heaven's Gate clear sky chart from 2005-11-06 to 2024-11-01.

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	7% 11% 4 8% 5% 4 4 4 5% 6% 42%	101117
	Night	7% 11% 4 8% 5% 5% 4 4 5% 6% 40%	97973
Transparency	Day	42% 7% 9% 19% 15% 8%	100861
	Night	44% 8% 11% 19% 13% 5%	97818
Seeing	Day	17% 22% 32% 20% 7% 1	14328
	Night	17% 13% 29% 28% 11% 1	23788

By Month

Percentage Cloud Cover SW (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	5% 15% 10% 17% 7% 6% 6% 5% 5% 6% 17%	2539
	11th to 20th	Day	6% 17% 8% 18% 7% 4 4 3 4 5% 25%	2540
	21st to end	Day	6% 17% 5% 12% 8% 7% 7% 5% 6% 6% 21%	2794
February	1st to 10th	Day	8% 21% 6% 13% 6% 4 5% 3 6% 6% 22%	1571
	11th to 20th	Day	6% 19% 8% 14% 8% 5% 5% 4 5% 5% 21%	1850
	21st to end	Day	5% 20% 8% 18% 8% 6% 5% 4 5% 4 17%	1570
March	1st to 10th	Day	4 13% 7% 15% 8% 7% 6% 5% 5% 6% 24%	3138
	11th to 20th	Day	4 14% 6% 9% 6% 4 5% 3 3 4 42%	3329
	21st to end	Day	6% 20% 7% 16% 9% 7% 8% 5% 6% 4 10%	4038
April	1st to 10th	Day	10% 20% 6% 11% 6% 5% 5% 4 6% 5% 21%	2280
	11th to 20th	Day	10% 17% 5% 10% 6% 5% 4 3 5% 6% 29%	2309
	21st to end	Day	16% 19% 4 9% 7% 4 4 3 5% 6% 25%	2470
May	1st to 10th	Day	9% 19% 4 8% 5% 5% 4 3 5% 5% 33%	4110
	11th to 20th	Day	10% 7% 2 6% 4 4 4 3 6% 7% 47%	4367
	21st to end	Day	14% 13% 4 8% 5% 5% 5% 4 5% 7% 31%	4813
June	1st to 10th	Day	16% 11% 3 8% 6% 4 5% 4 6% 8% 29%	2660
	11th to 20th	Day	15% 9% 3 7% 6% 5% 4 4 5% 5% 37%	2660
	21st to end	Day	7% 3 2 5% 3 3 4 3 5% 7% 58%	2660
July	1st to 10th	Day	2 2 3 2 3 3 3 4 5% 73%	4420
	11th to 20th	Day	1 2 1 2 2 2 3 3 4 5% 75%	4420
	21st to end	Day	2 2 1 2 3 2 3 3 5% 6% 73%	4790
August	1st to 10th	Day	3 2 1 4 4 4 4 4 6% 8% 60%	4349
	11th to 20th	Day	2 2 1 3 3 3 4 3 5% 7% 65%	4028
	21st to end	Day	3 3 1 3 3 3 3 3 4 6% 68%	4247
September	1st to 10th	Day	5% 3 1 4 3 3 4 2 4 6% 65%	2280
	11th to 20th	Day	7% 5% 2 6% 4 4 5% 4 5% 7% 52%	2128
	21st to end	Day	8% 6% 2 5% 3 4 4 4 5% 7% 52%	2090
October	1st to 10th	Day	13% 11% 3 6% 5% 4 3 3 4 5% 44%	2090
	11th to 20th	Day	11% 9% 3 8% 5% 4 4 3 4 7% 42%	1783
	21st to end	Day	12% 13% 4 8% 6% 5% 5% 4 5% 7% 32%	1881
November	1st to 10th	Day	12% 16% 4 9% 6% 4 4 3 5% 7% 28%	1674
	11th to 20th	Day	9% 15% 5% 10% 6% 7% 6% 5% 6% 7% 24%	1710
	21st to end	Day	6% 16% 5% 9% 6% 5% 5% 4 6% 6% 31%	1576
December	1st to 10th	Day	9% 15% 5% 9% 8% 5% 6% 5% 6% 6% 27%	1368
	11th to 20th	Day	6% 15% 6% 14% 8% 6% 7% 4 7% 8% 19%	1791
	21st to end	Day	6% 15% 7% 12% 6% 5% 5% 4 6% 8% 26%	2794
January	1st to 10th	Night	7% 16% 8% 14% 7% 5% 5% 4 6% 8% 20%	4406
	11th to 20th	Night	9% 17% 8% 14% 7% 5% 5% 3 5% 6% 20%	4420
	21st to end	Night	4 15% 5% 13% 7% 7% 6% 5% 6% 6% 25%	4862
February	1st to 10th	Night	9% 19% 7% 13% 7% 5% 5% 4 5% 5% 21%	2606
	11th to 20th	Night	7% 20% 6% 11% 7% 7% 5% 4 5% 5% 24%	2218
	21st to end	Night	5% 17% 7% 15% 10% 7% 5% 4 5% 7% 19%	1884
March	1st to 10th	Night	4 12% 6% 12% 6% 6% 6% 5% 6% 6% 30%	3736
	11th to 20th	Night	5% 12% 6% 10% 5% 4 4 3 4 5% 41%	3650
	21st to end	Night	8% 16% 5% 13% 7% 6% 7% 5% 8% 8% 16%	3612
April	1st to 10th	Night	9% 18% 6% 11% 6% 5% 4 4 5% 5% 27%	1900
	11th to 20th	Night	13% 13% 3 8% 6% 4 5% 4 5% 5% 35%	1819
	21st to end	Night	14% 13% 4 9% 5% 4 4 4 5% 7% 30%	1710
May	1st to 10th	Night	12% 14% 3 7% 5% 4 3 3 5% 6% 39%	2860
	11th to 20th	Night	7% 6% 2 5% 4 3 4 4 5% 7% 53%	2523
	21st to end	Night	17% 13% 3 6% 4 3 4 2 4 7% 38%	2762
June	1st to 10th	Night	16% 8% 2 6% 6% 5% 4 4 6% 7% 35%	1520
	11th to 20th	Night	16% 7% 2 4 3 4 4 3 5% 8% 44%	1520
	21st to end	Night	6% 4 2 4 3 3 5% 3 5% 8% 58%	1520
July	1st to 10th	Night	1 1 2 2 2 2 3 4 5% 79%	2540
	11th to 20th	Night	1 1 1 1 2 2 2 4 5% 81%	2540
	21st to end	Night	2 2 1 2 2 2 3 3 5% 7% 70%	2761
August	1st to 10th	Night	2 3 1 4 3 2 4 3 5% 9% 64%	2582
	11th to 20th	Night	1 1 2 2 3 3 3 6% 8% 71%	2811
	21st to end	Night	4 4 1 3 2 3 3 3 4 4 69%	3425
September	1st to 10th	Night	4 2 1 3 3 3 3 3 6% 7% 66%	1900
	11th to 20th	Night	6% 5% 2 4 3 4 4 4 6% 7% 55%	2052
	21st to end	Night	11% 5% 2 5% 3 3 3 2 5% 6% 55%	2090
October	1st to 10th	Night	11% 9% 3 5% 4 4 4 3 4 6% 46%	2090
	11th to 20th	Night	9% 10% 3 7% 5% 4 4 4 5% 6% 43%	2394
	21st to end	Night	12% 12% 4 8% 6% 5% 5% 4 4 6% 34%	2717
November	1st to 10th	Night	13% 13% 4 8% 5% 5% 5% 4 6% 7% 30%	2411
	11th to 20th	Night	12% 14% 4 10% 5% 5% 6% 4 6% 6% 28%	2470
	21st to end	Night	6% 15% 5% 11% 6% 5% 4 3 5% 6% 33%	2603
December	1st to 10th	Night	8% 13% 4 9% 7% 6% 6% 4 6% 7% 29%	2785
	11th to 20th	Night	5% 14% 5% 11% 7% 7% 6% 5% 7% 8% 24%	3412
	21st to end	Night	6% 15% 6% 12% 6% 5% 5% 4 5% 7% 29%	4862

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	67% 10% 12% 8% 1 1	2539
	11th to 20th	Day	64% 5% 9% 12% 8% 2	2540
	21st to end	Day	64% 11% 13% 8% 4	2794
February	1st to 10th	Day	63% 11% 11% 13% 2	1571
	11th to 20th	Day	66% 7% 10% 11% 5%	1860
	21st to end	Day	70% 8% 8% 9% 5% 1	1570
March	1st to 10th	Day	57% 13% 7% 13% 10%	3138
	11th to 20th	Day	45% 7% 7% 38% 3	3329
	21st to end	Day	70% 11% 9% 8% 2	4038
April	1st to 10th	Day	63% 8% 12% 14% 3	2280
	11th to 20th	Day	55% 7% 11% 16% 10% 1	2312
	21st to end	Day	60% 7% 10% 16% 7%	2470
May	1st to 10th	Day	49% 7% 8% 23% 12% 1	4110
	11th to 20th	Day	33% 7% 9% 35% 12% 4	4370
	21st to end	Day	49% 9% 13% 23% 5%	4814
June	1st to 10th	Day	51% 8% 12% 22% 7%	2660
	11th to 20th	Day	47% 6% 9% 20% 14% 3	2660
	21st to end	Day	26% 5% 8% 29% 27% 6%	2660
July	1st to 10th	Day	13% 4 5% 13% 26% 38%	4351
	11th to 20th	Day	11% 4 4 11% 25% 45%	4345
	21st to end	Day	12% 4 4 16% 40% 25%	4639
August	1st to 10th	Day	20% 6% 6% 17% 34% 18%	4333
	11th to 20th	Day	16% 5% 6% 23% 36% 14%	4067
	21st to end	Day	17% 5% 5% 27% 33% 12%	4246
September	1st to 10th	Day	21% 3 9% 23% 28% 16%	2280
	11th to 20th	Day	30% 6% 11% 22% 23% 9%	2128
	21st to end	Day	32% 4 10% 29% 20% 4	2090
October	1st to 10th	Day	43% 5% 9% 23% 18% 2	2090
	11th to 20th	Day	42% 5% 12% 25% 14% 1	1783
	21st to end	Day	51% 9% 10% 18% 11% 1	1881
November	1st to 10th	Day	56% 9% 13% 17% 5% 1	1674
	11th to 20th	Day	58% 10% 15% 14% 4	1710
	21st to end	Day	54% 8% 14% 15% 9% 1	1576
December	1st to 10th	Day	58% 14% 11% 10% 6% 1	1368
	11th to 20th	Day	63% 15% 10% 10% 2	1791
	21st to end	Day	55% 14% 13% 13% 5% 1	2794
January	1st to 10th	Night	63% 10% 14% 11% 1 1	4406
	11th to 20th	Night	64% 7% 9% 14% 6% 1	4420
	21st to end	Night	58% 16% 11% 11% 4	4862
February	1st to 10th	Night	66% 9% 10% 12% 2 1	2606
	11th to 20th	Night	62% 8% 11% 13% 5% 1	2219
	21st to end	Night	66% 7% 8% 13% 5% 1	1884
March	1st to 10th	Night	50% 16% 8% 14% 13%	3736
	11th to 20th	Night	45% 7% 10% 35% 4	3650
	21st to end	Night	59% 12% 15% 11% 3	3612
April	1st to 10th	Night	56% 7% 14% 18% 4	1900
	11th to 20th	Night	51% 6% 11% 19% 10% 2	1819
	21st to end	Night	52% 6% 12% 21% 8%	1710
May	1st to 10th	Night	44% 7% 10% 25% 13% 2	2860
	11th to 20th	Night	27% 6% 12% 37% 18%	2523
	21st to end	Night	45% 4 18% 27% 5%	2762
June	1st to 10th	Night	45% 9% 18% 22% 6%	1520
	11th to 20th	Night	38% 6% 14% 26% 13% 2	1520
	21st to end	Night	24% 5% 13% 30% 22% 5%	1520
July	1st to 10th	Night	9% 3 6% 16% 30% 36%	2500
	11th to 20th	Night	8% 3 5% 16% 26% 42%	2492
	21st to end	Night	13% 4 4 22% 38% 20%	2674
August	1st to 10th	Night	17% 6% 5% 20% 40% 13%	2574
	11th to 20th	Night	11% 5% 6% 27% 36% 14%	2838
	21st to end	Night	18% 5% 5% 29% 32% 11%	3425
September	1st to 10th	Night	18% 5% 9% 25% 29% 15%	1900
	11th to 20th	Night	27% 6% 10% 24% 23% 10%	2052
	21st to end	Night	30% 4 10% 28% 19% 8%	2090
October	1st to 10th	Night	39% 6% 10% 24% 18% 3	2090
	11th to 20th	Night	40% 6% 13% 23% 16% 2	2394
	21st to end	Night	50% 9% 9% 19% 13% 1	2717
November	1st to 10th	Night	52% 10% 10% 19% 7% 2	2411
	11th to 20th	Night	56% 10% 13% 18% 4	2470
	21st to end	Night	52% 6% 11% 18% 11% 1	2603
December	1st to 10th	Night	54% 12% 14% 13% 6% 2	2785
	11th to 20th	Night	57% 15% 11% 13% 3 1	3412
	21st to end	Night	55% 9% 15% 14% 5% 2	4862

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	23% 22% 39% 13% 3 1	180
	11th to 20th	Day	26% 27% 29% 7% 10% 1	180
	21st to end	Day	20% 24% 36% 18% 2	198
February	1st to 10th	Day	22% 34% 34% 8% 1	216
	11th to 20th	Day	21% 34% 30% 12% 3	455
	21st to end	Day	24% 30% 33% 11% 2	382
March	1st to 10th	Day	22% 36% 29% 11% 2	460
	11th to 20th	Day	17% 30% 32% 14% 5% 2	460
	21st to end	Day	25% 32% 26% 13% 4	506
April	1st to 10th	Day	25% 25% 30% 15% 5% 1	460
	11th to 20th	Day	25% 25% 27% 17% 4 1	452
	21st to end	Day	29% 25% 24% 16% 5% 1	460
May	1st to 10th	Day	19% 22% 32% 20% 6% 1	463
	11th to 20th	Day	28% 18% 27% 17% 7% 2	488
	21st to end	Day	25% 14% 26% 26% 7% 3	529
June	1st to 10th	Day	19% 18% 32% 23% 7% 2	490
	11th to 20th	Day	21% 26% 30% 17% 4 1	490
	21st to end	Day	8% 18% 37% 26% 8% 2	490
July	1st to 10th	Day	5% 16% 43% 26% 9% 2	486
	11th to 20th	Day	4 21% 38% 27% 8% 1	484
	21st to end	Day	3 16% 41% 27% 12% 2	531
August	1st to 10th	Day	6% 14% 37% 30% 11% 2	487
	11th to 20th	Day	5% 12% 31% 34% 14% 3	477
	21st to end	Day	6% 16% 36% 27% 12% 3	539
September	1st to 10th	Day	8% 14% 31% 30% 12% 4	490
	11th to 20th	Day	10% 18% 31% 28% 10% 2	490
	21st to end	Day	13% 18% 35% 22% 10% 2	490
October	1st to 10th	Day	19% 21% 29% 21% 9% 2	490
	11th to 20th	Day	16% 22% 33% 17% 10% 2	371
	21st to end	Day	26% 24% 27% 18% 5% 1	330
November	1st to 10th	Day	28% 20% 30% 18% 3	270
	11th to 20th	Day	20% 26% 26% 23% 5% 1	270
	21st to end	Day	17% 22% 39% 21% 2	206
December	1st to 10th	Day	24% 22% 27% 16% 11% 1	180
	11th to 20th	Day	24% 37% 27% 9% 3	180
	21st to end	Day	26% 31% 29% 8% 5% 2	198
January	1st to 10th	Night	24% 19% 34% 17% 5%	760
	11th to 20th	Night	24% 19% 31% 21% 6% 1	760
	21st to end	Night	17% 20% 32% 25% 5% 1	836
February	1st to 10th	Night	21% 20% 39% 17% 3 1	760
	11th to 20th	Night	20% 19% 34% 24% 3	744
	21st to end	Night	18% 23% 35% 18% 6%	628
March	1st to 10th	Night	18% 23% 34% 20% 6% 1	760
	11th to 20th	Night	16% 18% 32% 23% 10% 1	760
	21st to end	Night	19% 16% 36% 24% 5%	836
April	1st to 10th	Night	19% 14% 29% 26% 11% 1	760
	11th to 20th	Night	20% 13% 32% 25% 9% 1	691
	21st to end	Night	22% 10% 27% 31% 9% 1	570
May	1st to 10th	Night	19% 9% 26% 35% 11% 1	570
	11th to 20th	Night	14% 9% 23% 32% 22% 1	381
	21st to end	Night	23% 8% 18% 31% 19% 2	411
June	1st to 10th	Night	18% 6% 22% 34% 17% 2	380
	11th to 20th	Night	20% 6% 27% 33% 13%	380
	21st to end	Night	8% 5% 24% 42% 21%	380
July	1st to 10th	Night	5% 3 18% 52% 21% 1	370
	11th to 20th	Night	3 1 23% 58% 15%	368
	21st to end	Night	3 3 19% 51% 22%	416
August	1st to 10th	Night	5% 3 20% 45% 27%	405
	11th to 20th	Night	3 2 20% 46% 27% 2	564
	21st to end	Night	6% 4 24% 39% 25% 2	789
September	1st to 10th	Night	5% 3 18% 47% 24% 3	760
	11th to 20th	Night	7% 6% 21% 36% 25% 5%	760
	21st to end	Night	14% 6% 23% 31% 22% 3	760
October	1st to 10th	Night	16% 7% 25% 34% 17% 1	760
	11th to 20th	Night	16% 11% 26% 32% 13% 3	760
	21st to end	Night	23% 11% 31% 24% 8% 3	836
November	1st to 10th	Night	21% 15% 36% 24% 4	742
	11th to 20th	Night	24% 18% 34% 19% 4 1	760
	21st to end	Night	16% 19% 34% 22% 8% 1	760
December	1st to 10th	Night	19% 18% 35% 22% 5%	885
	11th to 20th	Night	20% 23% 36% 18% 3	890
	21st to end	Night	22% 24% 37% 14% 2 1	836

Page generated at 2024-10-29 09:20:49. Version ac07

Copyright © 2024 Attilla Danko.