Lava Springs Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lava Springs Star Party clear sky chart from 2005-11-06 to 2024-11-30.

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	6% 10% 3 7% 4 4 4 3 5% 6% 49%	105521
	Night	7% 10% 3 7% 4 4 4 3 5% 6% 46%	102740
Transparency	Day	35% 5% 10% 20% 19% 11%	105274
	Night	37% 5% 11% 19% 17% 9%	102575
Seeing	Day	11% 13% 26% 28% 17% 5%	15341
	Night	11% 5% 19% 41% 21% 2	25062

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	6% 22% 9% 14% 5% 4 4 2 3 5% 27%	2539
	11th to 20th	Day	7% 24% 8% 12% 5% 3 3 3 3 4 29%	2776
	21st to end	Day	10% 25% 5% 11% 5% 4 3 2 4 4 26%	3146
February	1st to 10th	Day	10% 19% 8% 10% 4 5% 4 4 5% 5% 26%	1710
	11th to 20th	Day	8% 20% 6% 11% 5% 4 4 3 4 5% 29%	1699
	21st to end	Day	7% 20% 7% 15% 5% 4 5% 3 4 5% 25%	1570
March	1st to 10th	Day	7% 21% 6% 11% 5% 4 3 2 4 4 32%	3314
	11th to 20th	Day	6% 12% 4 6% 4 4 4 3 5% 6% 46%	3490
	21st to end	Day	10% 20% 6% 10% 6% 6% 6% 4 5% 7% 20%	3825
April	1st to 10th	Day	12% 14% 4 8% 5% 4 4 5% 5% 6% 33%	2131
	11th to 20th	Day	9% 13% 3 7% 6% 4 5% 4 4 6% 38%	2437
	21st to end	Day	9% 12% 3 8% 5% 4 4 3 7% 7% 38%	2470
May	1st to 10th	Day	9% 14% 3 7% 5% 5% 4 4 6% 6% 37%	4110
	11th to 20th	Day	5% 4 2 5% 4 4 4 4 6% 7% 55%	4071
	21st to end	Day	8% 7% 2 7% 5% 4 4 4 5% 6% 47%	4655
June	1st to 10th	Day	7% 5% 2 5% 4 4 5% 4 6% 8% 49%	2698
	11th to 20th	Day	8% 5% 2 5% 3 4 4 3 5% 8% 53%	2850
	21st to end	Day	3 2 1 3 3 3 3 3 4 6% 69%	2850
July	1st to 10th	Day	2 1 1 2 2 1 2 2 4 5% 79%	4533
	11th to 20th	Day	2 2 1 4 3 3 4 3 5% 6% 66%	4275
	21st to end	Day	4 2 1 4 3 4 4 3 6% 7% 62%	4454
August	1st to 10th	Day	4 3 1 4 3 3 4 4 6% 7% 61%	4092
	11th to 20th	Day	3 2 1 3 3 3 4 3 6% 6% 67%	4028
	21st to end	Day	3 2 1 3 2 2 3 2 4 6% 72%	4521
September	1st to 10th	Day	5% 3 1 4 3 2 3 4 4 5% 66%	2177
	11th to 20th	Day	6% 3 1 4 3 3 3 4 5% 7% 62%	2090
	21st to end	Day	8% 4 1 3 3 3 3 2 4 4 65%	2090
October	1st to 10th	Day	7% 4 1 3 2 3 3 3 4 5% 65%	3316
	11th to 20th	Day	5% 7% 2 6% 3 3 4 2 4 6% 59%	3150
	21st to end	Day	5% 11% 3 6% 4 3 4 3 6% 8% 47%	3319
November	1st to 10th	Day	11% 12% 4 8% 5% 4 4 3 4 6% 39%	1764
	11th to 20th	Day	10% 14% 4 5% 4 3 4 4 5% 7% 40%	1730
	21st to end	Day	6% 14% 4 8% 4 4 3 4 4 6% 41%	1596
December	1st to 10th	Day	10% 16% 7% 11% 6% 3 4 3 4 5% 32%	1520
	11th to 20th	Day	10% 16% 5% 13% 5% 6% 5% 4 6% 8% 23%	1926
	21st to end	Day	7% 14% 5% 12% 5% 5% 6% 5% 5% 7% 30%	2599
January	1st to 10th	Night	6% 17% 9% 16% 4 3 4 3 4 6% 27%	4406
	11th to 20th	Night	9% 21% 7% 17% 5% 4 3 2 4 5% 24%	4172
	21st to end	Night	9% 26% 6% 10% 5% 4 5% 3 3 5% 25%	4521
February	1st to 10th	Night	9% 16% 4 12% 6% 4 5% 3 6% 6% 28%	2470
	11th to 20th	Night	8% 16% 5% 8% 4 4 3 3 5% 7% 36%	2364
	21st to end	Night	6% 17% 7% 13% 5% 4 4 4 6% 6% 31%	1884
March	1st to 10th	Night	7% 16% 4 8% 5% 5% 5% 4 6% 7% 32%	3560
	11th to 20th	Night	4 11% 3 5% 4 4 4 3 6% 8% 47%	3490
	21st to end	Night	8% 14% 4 7% 6% 6% 5% 5% 6% 7% 33%	3828
April	1st to 10th	Night	9% 13% 3 6% 4 4 4 4 6% 6% 41%	2043
	11th to 20th	Night	9% 12% 3 7% 5% 4 4 3 5% 6% 42%	1691
	21st to end	Night	9% 8% 2 7% 4 3 4 4 6% 6% 49%	1710
May	1st to 10th	Night	7% 13% 3 8% 5% 4 4 3 5% 6% 41%	2860
	11th to 20th	Night	6% 4 2 4 4 5% 3 4 5% 8% 56%	2834
	21st to end	Night	8% 5% 1 6% 4 4 5% 3 6% 7% 51%	2928
June	1st to 10th	Night	5% 4 2 6% 5% 4 4 5% 7% 9% 50%	1477
	11th to 20th	Night	8% 4 1 4 3 3 4 3 6% 7% 56%	1330
	21st to end	Night	4 2 1 3 2 3 2 3 4 7% 68%	1330
July	1st to 10th	Night	2 2 1 3 2 3 3 2 5% 4 74%	2408
	11th to 20th	Night	1 2 1 3 3 3 3 3 5% 8% 67%	2686
	21st to end	Night	2 2 1 5% 4 3 3 3 5% 7% 65%	3109
August	1st to 10th	Night	2 3 2 4 3 4 5% 4 6% 8% 60%	2847
	11th to 20th	Night	3 3 1 5% 4 4 4 3 5% 5% 64%	2811
	21st to end	Night	2 2 1 3 3 2 3 2 3 5% 73%	3146
September	1st to 10th	Night	3 3 1 4 3 3 3 3 4 5% 69%	1998
	11th to 20th	Night	6% 3 1 4 3 3 3 3 4 6% 64%	2090
	21st to end	Night	7% 3 1 4 2 3 3 2 3 5% 66%	2090
October	1st to 10th	Night	5% 4 1 3 2 2 2 2 4 5% 70%	3645
	11th to 20th	Night	9% 7% 2 5% 3 3 3 3 4 6% 55%	3778
	21st to end	Night	6% 10% 2 6% 3 4 4 4 5% 6% 49%	4236
November	1st to 10th	Night	10% 10% 3 7% 4 4 4 5% 4 6% 44%	2535
	11th to 20th	Night	8% 11% 4 7% 5% 4 4 4 6% 6% 41%	2648
	21st to end	Night	6% 12% 4 9% 5% 4 4 3 6% 6% 40%	2800
December	1st to 10th	Night	10% 17% 4 9% 5% 3 4 3 5% 6% 33%	2660
	11th to 20th	Night	11% 14% 5% 12% 6% 6% 5% 3 5% 5% 28%	3271
	21st to end	Night	8% 14% 6% 11% 5% 5% 5% 5% 7% 6% 30%	5084

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	61% 7% 13% 16% 3	2539
	11th to 20th	Day	62% 5% 13% 13% 7% 1	2776
	21st to end	Day	62% 7% 12% 12% 6% 1	3146
February	1st to 10th	Day	59% 8% 11% 16% 5% 1	1710
	11th to 20th	Day	58% 4 14% 15% 7% 2	1708
	21st to end	Day	60% 5% 12% 15% 6% 2	1570
March	1st to 10th	Day	55% 5% 9% 19% 12% 1	3314
	11th to 20th	Day	38% 5% 12% 31% 14% 1	3490
	21st to end	Day	60% 8% 12% 15% 4	3825
April	1st to 10th	Day	52% 6% 12% 17% 11% 3	2131
	11th to 20th	Day	46% 5% 10% 23% 13% 2	2440
	21st to end	Day	43% 6% 12% 25% 14% 1	2470
May	1st to 10th	Day	42% 6% 11% 22% 16% 3	4110
	11th to 20th	Day	25% 5% 10% 37% 20% 4	4074
	21st to end	Day	35% 7% 10% 30% 17% 1	4655
June	1st to 10th	Day	31% 6% 13% 28% 19% 2	2698
	11th to 20th	Day	28% 5% 11% 22% 25% 9%	2850
	21st to end	Day	16% 3 6% 19% 37% 19%	2850
July	1st to 10th	Day	10% 2 4 11% 23% 51%	4464
	11th to 20th	Day	17% 3 4 10% 25% 41%	4200
	21st to end	Day	20% 4 5% 12% 32% 28%	4314
August	1st to 10th	Day	20% 5% 5% 16% 30% 24%	4078
	11th to 20th	Day	16% 4 6% 16% 37% 21%	4067
	21st to end	Day	14% 2 6% 18% 32% 28%	4520
September	1st to 10th	Day	20% 4 7% 16% 31% 22%	2177
	11th to 20th	Day	21% 4 8% 23% 29% 15%	2090
	21st to end	Day	23% 3 8% 25% 32% 9%	2090
October	1st to 10th	Day	23% 3 6% 17% 33% 18%	3316
	11th to 20th	Day	28% 4 7% 34% 20% 7%	3150
	21st to end	Day	34% 5% 16% 27% 16%	3319
November	1st to 10th	Day	46% 6% 14% 22% 11% 2	1764
	11th to 20th	Day	43% 6% 18% 22% 9% 1	1730
	21st to end	Day	45% 5% 16% 22% 11% 2	1596
December	1st to 10th	Day	55% 7% 14% 15% 6% 3	1520
	11th to 20th	Day	57% 9% 15% 17% 3	1924
	21st to end	Day	51% 7% 18% 16% 9%	2599
January	1st to 10th	Night	57% 6% 13% 18% 6%	4406
	11th to 20th	Night	64% 6% 11% 14% 4 1	4172
	21st to end	Night	62% 7% 13% 10% 6% 1	4521
February	1st to 10th	Night	55% 7% 15% 17% 6%	2470
	11th to 20th	Night	48% 6% 15% 20% 10% 1	2365
	21st to end	Night	54% 4 14% 20% 7% 2	1884
March	1st to 10th	Night	48% 7% 12% 20% 12% 1	3560
	11th to 20th	Night	33% 7% 17% 26% 17% 1	3490
	21st to end	Night	46% 10% 15% 24% 5% 1	3828
April	1st to 10th	Night	42% 7% 14% 19% 14% 4	2043
	11th to 20th	Night	42% 4 14% 23% 15% 2	1691
	21st to end	Night	35% 5% 14% 26% 19%	1710
May	1st to 10th	Night	41% 6% 11% 21% 19% 3	2860
	11th to 20th	Night	24% 6% 11% 29% 23% 7%	2835
	21st to end	Night	29% 7% 13% 26% 22% 3	2928
June	1st to 10th	Night	27% 8% 15% 25% 23% 3	1477
	11th to 20th	Night	25% 6% 10% 23% 24% 12%	1330
	21st to end	Night	16% 3 5% 17% 31% 27%	1330
July	1st to 10th	Night	14% 2 3 10% 19% 51%	2368
	11th to 20th	Night	15% 3 3 11% 25% 43%	2638
	21st to end	Night	18% 3 4 11% 34% 31%	3011
August	1st to 10th	Night	19% 5% 5% 12% 25% 34%	2838
	11th to 20th	Night	22% 3 5% 13% 35% 22%	2838
	21st to end	Night	15% 3 5% 16% 33% 29%	3146
September	1st to 10th	Night	18% 3 8% 13% 28% 30%	1998
	11th to 20th	Night	21% 4 8% 22% 27% 19%	2090
	21st to end	Night	23% 4 6% 23% 35% 10%	2090
October	1st to 10th	Night	18% 3 7% 17% 37% 17%	3645
	11th to 20th	Night	32% 3 7% 30% 20% 8%	3778
	21st to end	Night	34% 5% 10% 30% 18% 3	4236
November	1st to 10th	Night	40% 6% 13% 23% 16% 2	2535
	11th to 20th	Night	41% 5% 17% 24% 12% 1	2648
	21st to end	Night	43% 5% 15% 24% 11% 2	2800
December	1st to 10th	Night	51% 7% 17% 16% 7% 3	2660
	11th to 20th	Night	56% 7% 14% 16% 7%	3272
	21st to end	Night	50% 7% 17% 16% 10%	5084

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	21% 16% 20% 23% 15% 4	180
	11th to 20th	Day	14% 11% 29% 27% 16% 3	249
	21st to end	Day	14% 12% 28% 30% 14% 3	297
February	1st to 10th	Day	22% 17% 27% 27% 7%	270
	11th to 20th	Day	15% 18% 33% 23% 7% 4	304
	21st to end	Day	13% 23% 32% 23% 8% 1	382
March	1st to 10th	Day	18% 19% 35% 22% 5% 1	460
	11th to 20th	Day	12% 19% 31% 26% 9% 3	460
	21st to end	Day	19% 25% 31% 18% 6%	506
April	1st to 10th	Day	23% 19% 24% 23% 9% 2	460
	11th to 20th	Day	18% 25% 29% 18% 8% 2	452
	21st to end	Day	16% 20% 28% 21% 11% 4	460
May	1st to 10th	Day	11% 20% 31% 27% 8% 3	463
	11th to 20th	Day	14% 13% 29% 27% 13% 4	488
	21st to end	Day	12% 10% 24% 27% 20% 8%	629
June	1st to 10th	Day	8% 10% 22% 31% 24% 5%	680
	11th to 20th	Day	10% 13% 26% 32% 16% 3	680
	21st to end	Day	3 6% 23% 35% 25% 7%	680
July	1st to 10th	Day	4 5% 20% 40% 26% 5%	560
	11th to 20th	Day	2 4 30% 39% 21% 4	484
	21st to end	Day	2 3 19% 40% 27% 9%	531
August	1st to 10th	Day	6% 6% 25% 33% 23% 7%	487
	11th to 20th	Day	4 7% 25% 29% 25% 10%	477
	21st to end	Day	5% 8% 22% 28% 25% 11%	539
September	1st to 10th	Day	4 8% 22% 28% 27% 11%	490
	11th to 20th	Day	6% 11% 28% 24% 21% 9%	490
	21st to end	Day	8% 11% 24% 28% 20% 9%	490
October	1st to 10th	Day	13% 11% 21% 24% 20% 12%	394
	11th to 20th	Day	10% 14% 17% 24% 24% 11%	300
	21st to end	Day	13% 15% 22% 32% 16% 2	330
November	1st to 10th	Day	14% 17% 23% 29% 11% 7%	300
	11th to 20th	Day	15% 12% 25% 30% 15% 3	300
	21st to end	Day	12% 14% 26% 30% 15% 2	299
December	1st to 10th	Day	16% 12% 22% 34% 11% 6%	270
	11th to 20th	Day	15% 14% 31% 28% 11%	270
	21st to end	Day	20% 16% 27% 25% 9% 3	230
January	1st to 10th	Night	17% 6% 19% 38% 18% 2	760
	11th to 20th	Night	18% 6% 20% 36% 18% 3	760
	21st to end	Night	17% 6% 21% 36% 17% 2	836
February	1st to 10th	Night	16% 7% 26% 38% 12% 1	760
	11th to 20th	Night	13% 7% 24% 41% 14% 1	744
	21st to end	Night	12% 9% 28% 37% 13% 1	628
March	1st to 10th	Night	13% 8% 24% 43% 11% 2	760
	11th to 20th	Night	10% 6% 24% 42% 18%	760
	21st to end	Night	14% 8% 23% 41% 13% 1	836
April	1st to 10th	Night	14% 9% 22% 38% 15% 1	727
	11th to 20th	Night	13% 9% 29% 37% 11% 1	563
	21st to end	Night	11% 8% 21% 36% 21% 2	570
May	1st to 10th	Night	11% 5% 24% 40% 18% 2	570
	11th to 20th	Night	10% 5% 15% 38% 29% 3	561
	21st to end	Night	13% 5% 17% 37% 24% 4	617
June	1st to 10th	Night	6% 5% 16% 42% 28% 2	527
	11th to 20th	Night	9% 2 22% 44% 21% 1	380
	21st to end	Night	5% 1 10% 49% 29% 5%	380
July	1st to 10th	Night	1 1 11% 47% 35% 4	370
	11th to 20th	Night	2 1 9% 58% 28% 1	449
	21st to end	Night	2 1 7% 48% 39% 3	624
August	1st to 10th	Night	5% 2 8% 51% 33% 2	567
	11th to 20th	Night	2 2 12% 44% 37% 3	564
	21st to end	Night	4 2 13% 46% 30% 5%	627
September	1st to 10th	Night	4 2 13% 42% 35% 4	683
	11th to 20th	Night	7% 3 12% 43% 29% 7%	760
	21st to end	Night	9% 3 13% 39% 30% 6%	760
October	1st to 10th	Night	11% 3 17% 38% 29% 3	760
	11th to 20th	Night	13% 3 15% 37% 29% 3	760
	21st to end	Night	11% 4 19% 42% 21% 3	836
November	1st to 10th	Night	13% 6% 18% 42% 18% 3	780
	11th to 20th	Night	12% 7% 24% 41% 14% 2	848
	21st to end	Night	10% 7% 22% 40% 17% 3	1000
December	1st to 10th	Night	17% 8% 22% 41% 12%	950
	11th to 20th	Night	18% 7% 25% 38% 11% 1	950
	21st to end	Night	19% 9% 26% 34% 11% 1	1035

Page generated at 2024-11-27 15:30:51. Version ac07

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