Logan Valley Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Logan Valley Star Party clear sky chart from 2005-11-06 to 2024-11-10.

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 8% 5% 4 4 3 5% 6% 46%	105288
	Night	6% 10% 4 8% 5% 4 5% 4 5% 6% 44%	102530
Transparency	Day	35% 7% 9% 19% 18% 12%	105033
	Night	35% 9% 11% 19% 18% 8%	102374
Seeing	Day	14% 16% 29% 25% 12% 4	14543
	Night	13% 12% 20% 32% 19% 3	23701

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	7% 15% 8% 20% 7% 6% 6% 4 4 4 18%	2539
	11th to 20th	Day	10% 21% 6% 14% 5% 5% 4 4 4 3 24%	2540
	21st to end	Day	10% 23% 6% 10% 6% 5% 4 3 5% 5% 22%	2794
February	1st to 10th	Day	8% 15% 5% 11% 6% 4 5% 4 5% 6% 30%	1691
	11th to 20th	Day	7% 17% 7% 13% 6% 6% 4 3 6% 5% 26%	1799
	21st to end	Day	5% 17% 6% 15% 9% 5% 4 4 7% 5% 23%	1570
March	1st to 10th	Day	8% 17% 6% 17% 6% 5% 4 3 4 4 26%	3138
	11th to 20th	Day	5% 13% 4 8% 5% 4 3 3 4 5% 47%	3280
	21st to end	Day	7% 17% 7% 15% 7% 7% 6% 4 5% 5% 19%	4165
April	1st to 10th	Day	8% 14% 5% 13% 7% 5% 5% 4 5% 6% 27%	2280
	11th to 20th	Day	7% 13% 4 10% 7% 6% 5% 5% 6% 6% 34%	2249
	21st to end	Day	6% 12% 4 8% 5% 5% 5% 4 6% 7% 38%	2412
May	1st to 10th	Day	6% 12% 6% 9% 5% 4 4 4 4 5% 40%	4234
	11th to 20th	Day	6% 6% 2 5% 4 3 4 3 5% 6% 57%	4377
	21st to end	Day	6% 11% 3 9% 6% 5% 5% 4 5% 7% 39%	4813
June	1st to 10th	Day	11% 9% 4 7% 5% 5% 6% 4 6% 7% 35%	2660
	11th to 20th	Day	6% 7% 2 6% 5% 5% 5% 4 6% 7% 46%	2660
	21st to end	Day	4 4 1 4 3 4 3 3 5% 6% 62%	2660
July	1st to 10th	Day	1 2 1 2 2 2 3 2 4 4 79%	4420
	11th to 20th	Day	2 2 1 3 2 3 3 2 4 5% 74%	4420
	21st to end	Day	1 2 1 3 2 2 3 3 4 6% 74%	4790
August	1st to 10th	Day	5% 4 2 4 3 3 4 3 6% 7% 58%	4400
	11th to 20th	Day	2 2 1 4 3 3 3 3 4 5% 70%	3880
	21st to end	Day	3 3 1 3 3 3 3 3 4 5% 70%	4180
September	1st to 10th	Day	2 3 1 5% 3 2 3 2 4 5% 69%	2280
	11th to 20th	Day	6% 5% 2 5% 4 4 4 3 5% 6% 56%	2208
	21st to end	Day	4 6% 3 7% 5% 3 4 2 4 5% 57%	2090
October	1st to 10th	Day	5% 5% 2 5% 3 2 3 2 3 6% 64%	3306
	11th to 20th	Day	6% 8% 2 6% 4 4 4 3 4 7% 50%	3140
	21st to end	Day	10% 11% 4 8% 5% 5% 5% 4 8% 7% 34%	3101
November	1st to 10th	Day	12% 15% 4 8% 6% 4 5% 4 4 8% 31%	1755
	11th to 20th	Day	11% 13% 4 8% 5% 5% 6% 6% 6% 7% 27%	1695
	21st to end	Day	7% 12% 4 9% 6% 5% 6% 4 4 7% 35%	1520
December	1st to 10th	Day	10% 15% 5% 9% 7% 4 5% 4 6% 7% 29%	1520
	11th to 20th	Day	11% 19% 4 10% 6% 4 5% 4 8% 6% 22%	1928
	21st to end	Day	7% 13% 6% 13% 8% 6% 6% 5% 6% 8% 23%	2794
January	1st to 10th	Night	7% 18% 7% 16% 8% 6% 7% 5% 5% 4 17%	4406
	11th to 20th	Night	10% 20% 8% 12% 5% 4 5% 3 4 5% 25%	4420
	21st to end	Night	11% 20% 5% 10% 6% 5% 5% 4 5% 7% 23%	4862
February	1st to 10th	Night	7% 12% 5% 12% 7% 5% 6% 5% 6% 7% 29%	2488
	11th to 20th	Night	7% 12% 5% 10% 8% 6% 6% 4 6% 6% 30%	2267
	21st to end	Night	6% 13% 4 14% 8% 6% 6% 5% 6% 7% 26%	1884
March	1st to 10th	Night	5% 16% 6% 11% 6% 5% 4 4 5% 6% 32%	3736
	11th to 20th	Night	6% 11% 3 8% 5% 4 4 4 5% 5% 45%	3698
	21st to end	Night	5% 11% 6% 13% 9% 8% 8% 6% 6% 7% 23%	3488
April	1st to 10th	Night	8% 11% 5% 9% 6% 6% 6% 4 5% 7% 33%	1900
	11th to 20th	Night	5% 11% 4 8% 6% 5% 4 5% 6% 5% 39%	1879
	21st to end	Night	6% 8% 3 7% 5% 5% 6% 6% 7% 9% 38%	1767
May	1st to 10th	Night	7% 10% 5% 10% 5% 4 6% 4 5% 4 39%	2715
	11th to 20th	Night	4 5% 2 4 3 3 3 3 5% 6% 62%	2516
	21st to end	Night	5% 10% 4 7% 5% 4 4 4 5% 5% 47%	2762
June	1st to 10th	Night	8% 9% 2 7% 4 4 5% 5% 7% 8% 41%	1520
	11th to 20th	Night	5% 7% 2 7% 4 4 3 3 6% 7% 54%	1520
	21st to end	Night	3 4 1 5% 3 2 3 4 4 6% 65%	1520
July	1st to 10th	Night	1 1 1 2 2 2 2 1 3 5% 81%	2540
	11th to 20th	Night	1 1 1 2 2 2 3 3 4 5% 77%	2540
	21st to end	Night	2 2 1 3 2 3 3 3 4 5% 73%	2761
August	1st to 10th	Night	3 3 2 4 3 3 4 4 6% 8% 61%	2529
	11th to 20th	Night	1 1 1 3 2 3 3 2 4 5% 73%	2960
	21st to end	Night	1 3 2 3 2 3 3 3 4 5% 73%	3498
September	1st to 10th	Night	3 2 1 3 2 3 3 3 4 6% 73%	1900
	11th to 20th	Night	3 3 1 5% 4 4 4 3 5% 7% 61%	1971
	21st to end	Night	5% 5% 2 4 3 3 4 3 5% 6% 60%	2090
October	1st to 10th	Night	3 4 2 4 3 2 3 2 4 5% 68%	3671
	11th to 20th	Night	5% 5% 2 6% 5% 4 4 4 7% 7% 52%	3796
	21st to end	Night	5% 7% 4 7% 5% 5% 5% 5% 7% 7% 44%	4457
November	1st to 10th	Night	11% 10% 3 9% 6% 5% 6% 4 5% 6% 35%	2528
	11th to 20th	Night	11% 11% 3 10% 6% 6% 5% 5% 6% 6% 31%	2483
	21st to end	Night	7% 12% 4 9% 6% 5% 5% 4 5% 6% 35%	2660
December	1st to 10th	Night	10% 12% 5% 9% 6% 5% 5% 4 5% 7% 31%	2660
	11th to 20th	Night	11% 15% 5% 10% 7% 6% 5% 5% 5% 5% 25%	3276
	21st to end	Night	8% 13% 4 12% 8% 6% 6% 5% 6% 7% 25%	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	56% 16% 14% 11% 2 1	2539
	11th to 20th	Day	60% 9% 9% 15% 5% 1	2540
	21st to end	Day	60% 12% 12% 9% 5% 1	2794
February	1st to 10th	Day	50% 10% 15% 18% 6% 1	1691
	11th to 20th	Day	53% 10% 11% 15% 9% 2	1809
	21st to end	Day	54% 11% 12% 13% 9% 1	1570
March	1st to 10th	Day	50% 12% 10% 15% 12% 1	3138
	11th to 20th	Day	33% 8% 12% 34% 13%	3280
	21st to end	Day	53% 15% 14% 13% 5%	4165
April	1st to 10th	Day	52% 8% 14% 17% 7% 2	2280
	11th to 20th	Day	43% 10% 13% 20% 12% 3	2252
	21st to end	Day	41% 9% 11% 21% 16% 1	2412
May	1st to 10th	Day	38% 10% 11% 24% 14% 2	4234
	11th to 20th	Day	24% 6% 9% 28% 26% 8%	4380
	21st to end	Day	35% 10% 14% 29% 11% 1	4814
June	1st to 10th	Day	42% 10% 10% 26% 12% 1	2660
	11th to 20th	Day	31% 8% 11% 23% 21% 6%	2660
	21st to end	Day	20% 5% 8% 23% 31% 12%	2660
July	1st to 10th	Day	10% 3 4 10% 18% 55%	4351
	11th to 20th	Day	14% 2 4 9% 19% 53%	4345
	21st to end	Day	12% 3 3 12% 34% 37%	4639
August	1st to 10th	Day	23% 3 4 13% 28% 29%	4384
	11th to 20th	Day	15% 3 4 15% 41% 23%	3920
	21st to end	Day	17% 3 5% 25% 26% 24%	4179
September	1st to 10th	Day	16% 4 5% 21% 30% 24%	2280
	11th to 20th	Day	27% 5% 8% 21% 26% 13%	2208
	21st to end	Day	28% 6% 8% 23% 24% 12%	2090
October	1st to 10th	Day	24% 4 6% 18% 37% 11%	3306
	11th to 20th	Day	34% 4 12% 27% 20% 4	3140
	21st to end	Day	44% 6% 8% 21% 19% 1	3101
November	1st to 10th	Day	48% 7% 13% 18% 13% 1	1755
	11th to 20th	Day	48% 11% 13% 18% 7% 1	1695
	21st to end	Day	44% 10% 13% 17% 13% 3	1520
December	1st to 10th	Day	50% 11% 16% 14% 8% 2	1520
	11th to 20th	Day	57% 10% 13% 13% 6% 1	1928
	21st to end	Day	53% 14% 14% 11% 8%	2794
January	1st to 10th	Night	54% 17% 17% 9% 3	4406
	11th to 20th	Night	56% 10% 12% 13% 6% 2	4420
	21st to end	Night	55% 13% 12% 13% 5% 2	4862
February	1st to 10th	Night	47% 13% 14% 17% 8% 1	2488
	11th to 20th	Night	47% 11% 15% 15% 10% 3	2268
	21st to end	Night	47% 13% 14% 15% 8% 3	1884
March	1st to 10th	Night	43% 11% 12% 18% 15% 2	3736
	11th to 20th	Night	33% 9% 10% 31% 17%	3698
	21st to end	Night	45% 18% 15% 15% 5% 2	3488
April	1st to 10th	Night	42% 9% 16% 22% 9% 1	1900
	11th to 20th	Night	38% 11% 14% 23% 13% 2	1879
	21st to end	Night	34% 12% 15% 23% 16% 1	1767
May	1st to 10th	Night	33% 13% 14% 24% 15% 1	2715
	11th to 20th	Night	20% 6% 11% 30% 32% 2	2516
	21st to end	Night	30% 12% 16% 32% 9%	2762
June	1st to 10th	Night	35% 11% 14% 28% 12%	1520
	11th to 20th	Night	26% 7% 14% 28% 19% 6%	1520
	21st to end	Night	20% 5% 9% 29% 28% 9%	1520
July	1st to 10th	Night	9% 2 4 14% 20% 52%	2500
	11th to 20th	Night	10% 2 3 12% 22% 49%	2492
	21st to end	Night	15% 2 3 11% 37% 33%	2674
August	1st to 10th	Night	21% 3 4 15% 31% 26%	2521
	11th to 20th	Night	14% 3 3 17% 42% 21%	2986
	21st to end	Night	13% 3 5% 25% 30% 24%	3498
September	1st to 10th	Night	13% 4 5% 22% 30% 26%	1900
	11th to 20th	Night	20% 7% 8% 22% 29% 15%	1971
	21st to end	Night	22% 6% 8% 24% 28% 12%	2090
October	1st to 10th	Night	19% 4 6% 19% 39% 13%	3671
	11th to 20th	Night	27% 5% 15% 21% 29% 3	3796
	21st to end	Night	33% 7% 10% 24% 23% 2	4457
November	1st to 10th	Night	43% 10% 11% 17% 16% 2	2528
	11th to 20th	Night	47% 10% 13% 18% 11% 1	2483
	21st to end	Night	43% 10% 12% 15% 16% 5%	2660
December	1st to 10th	Night	46% 11% 14% 15% 11% 3	2660
	11th to 20th	Night	54% 11% 11% 15% 8% 1	3276
	21st to end	Night	50% 14% 15% 10% 10% 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	31% 14% 24% 16% 12% 3	180
	11th to 20th	Day	27% 17% 24% 13% 16% 3	180
	21st to end	Day	17% 15% 35% 20% 11% 3	198
February	1st to 10th	Day	19% 28% 30% 17% 5% 2	351
	11th to 20th	Day	21% 23% 32% 17% 6%	431
	21st to end	Day	22% 21% 31% 21% 6%	382
March	1st to 10th	Day	22% 24% 32% 17% 5%	460
	11th to 20th	Day	20% 18% 31% 21% 7% 2	460
	21st to end	Day	24% 22% 28% 20% 5% 1	506
April	1st to 10th	Day	24% 19% 26% 18% 10% 2	460
	11th to 20th	Day	19% 26% 28% 16% 8% 3	452
	21st to end	Day	15% 20% 31% 25% 8% 1	460
May	1st to 10th	Day	15% 21% 29% 22% 9% 3	463
	11th to 20th	Day	21% 16% 27% 23% 10% 4	488
	21st to end	Day	17% 12% 22% 27% 17% 5%	529
June	1st to 10th	Day	12% 17% 30% 22% 12% 7%	490
	11th to 20th	Day	17% 19% 28% 23% 12% 2	490
	21st to end	Day	4 14% 31% 32% 15% 4	490
July	1st to 10th	Day	5% 8% 37% 34% 15% 2	486
	11th to 20th	Day	4 11% 33% 32% 14% 5%	484
	21st to end	Day	3 9% 32% 34% 18% 4	531
August	1st to 10th	Day	7% 6% 28% 38% 16% 5%	487
	11th to 20th	Day	4 6% 28% 33% 21% 9%	477
	21st to end	Day	6% 12% 26% 32% 17% 7%	539
September	1st to 10th	Day	5% 9% 26% 36% 18% 6%	490
	11th to 20th	Day	10% 10% 26% 30% 18% 6%	490
	21st to end	Day	10% 11% 32% 27% 16% 4	490
October	1st to 10th	Day	12% 14% 27% 27% 16% 4	490
	11th to 20th	Day	15% 14% 27% 25% 14% 5%	481
	21st to end	Day	16% 18% 26% 24% 13% 3	330
November	1st to 10th	Day	24% 14% 25% 26% 10% 1	297
	11th to 20th	Day	18% 16% 25% 28% 11% 2	263
	21st to end	Day	13% 17% 30% 28% 11% 2	180
December	1st to 10th	Day	25% 17% 21% 19% 10% 8%	180
	11th to 20th	Day	29% 20% 26% 16% 8% 1	180
	21st to end	Day	17% 22% 26% 21% 12% 1	198
January	1st to 10th	Night	19% 16% 21% 24% 16% 4	760
	11th to 20th	Night	22% 15% 17% 26% 17% 3	760
	21st to end	Night	17% 11% 17% 33% 19% 3	836
February	1st to 10th	Night	16% 18% 21% 30% 13% 2	760
	11th to 20th	Night	17% 14% 23% 26% 17% 2	744
	21st to end	Night	17% 16% 25% 27% 13% 2	628
March	1st to 10th	Night	15% 18% 23% 28% 14% 2	760
	11th to 20th	Night	16% 13% 22% 29% 18% 2	760
	21st to end	Night	16% 19% 22% 30% 12% 1	836
April	1st to 10th	Night	15% 14% 24% 29% 15% 3	760
	11th to 20th	Night	12% 18% 23% 26% 17% 4	751
	21st to end	Night	11% 16% 25% 32% 15% 1	627
May	1st to 10th	Night	12% 15% 30% 24% 18% 2	490
	11th to 20th	Night	12% 10% 20% 30% 24% 5%	374
	21st to end	Night	12% 9% 20% 30% 25% 5%	411
June	1st to 10th	Night	11% 8% 22% 36% 20% 2	380
	11th to 20th	Night	9% 13% 25% 36% 15% 2	380
	21st to end	Night	4 6% 22% 42% 24% 2	380
July	1st to 10th	Night	5% 4 21% 48% 20% 2	370
	11th to 20th	Night	2 4 27% 48% 18% 1	368
	21st to end	Night	2 3 22% 45% 26% 1	416
August	1st to 10th	Night	4 3 18% 45% 27% 3	378
	11th to 20th	Night	2 2 20% 37% 32% 6%	646
	21st to end	Night	4 5% 20% 39% 29% 3	836
September	1st to 10th	Night	4 3 18% 38% 33% 4	760
	11th to 20th	Night	6% 5% 14% 37% 31% 8%	760
	21st to end	Night	9% 8% 16% 33% 27% 8%	760
October	1st to 10th	Night	8% 7% 20% 34% 25% 6%	760
	11th to 20th	Night	12% 11% 16% 33% 23% 6%	760
	21st to end	Night	14% 10% 18% 36% 17% 6%	836
November	1st to 10th	Night	17% 13% 19% 33% 17% 1	778
	11th to 20th	Night	19% 15% 16% 32% 15% 3	760
	21st to end	Night	16% 16% 17% 29% 16% 6%	760
December	1st to 10th	Night	19% 10% 22% 28% 16% 4	760
	11th to 20th	Night	22% 12% 18% 30% 15% 2	760
	21st to end	Night	22% 19% 20% 27% 10% 2	836

Page generated at 2024-11-07 03:55:50. Version ac07

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