Long Point on Lake Chautauqua
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Long Point on Lake Chautauqua clear sky chart from 2005-11-06 to 2025-02-21.

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	16% 13% 5% 10% 5% 4 4 3 5% 6% 27%	108739
	Night	16% 15% 6% 12% 6% 4 4 3 4 5% 25%	109815
Transparency	Day	57% 4 11% 18% 9% 1	112379
	Night	60% 4 10% 17% 8% 1	114338
Seeing	Day	26% 16% 30% 18% 8% 3	14843
	Night	26% 16% 27% 21% 9% 1	24488

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	12% 21% 12% 31% 6% 2 3 2 2 2 7%	3671
	11th to 20th	Day	10% 24% 10% 23% 9% 6% 3 2 2 3 9%	4026
	21st to end	Day	18% 17% 8% 20% 8% 5% 5% 3 3 3 11%	4466
February	1st to 10th	Day	15% 21% 7% 17% 9% 6% 3 2 3 3 14%	1800
	11th to 20th	Day	14% 18% 8% 20% 8% 4 4 3 3 4 14%	1753
	21st to end	Day	17% 19% 5% 14% 7% 4 3 2 4 4 21%	1514
March	1st to 10th	Day	19% 14% 8% 9% 4 4 3 2 3 6% 28%	3432
	11th to 20th	Day	10% 22% 8% 11% 4 4 4 3 4 6% 26%	3480
	21st to end	Day	19% 15% 5% 12% 4 3 4 4 4 5% 27%	3815
April	1st to 10th	Day	16% 15% 5% 8% 5% 4 4 3 4 6% 28%	2233
	11th to 20th	Day	20% 15% 2 6% 4 3 4 3 5% 6% 32%	2283
	21st to end	Day	19% 14% 4 6% 4 4 4 3 4 5% 34%	2470
May	1st to 10th	Day	22% 10% 3 8% 4 4 4 3 5% 6% 31%	4108
	11th to 20th	Day	19% 10% 3 8% 5% 5% 4 3 5% 7% 30%	4258
	21st to end	Day	14% 5% 2 6% 5% 4 5% 4 6% 7% 43%	4837
June	1st to 10th	Day	17% 8% 2 6% 5% 3 4 4 6% 8% 36%	2660
	11th to 20th	Day	15% 6% 3 7% 5% 5% 5% 4 7% 8% 36%	2660
	21st to end	Day	16% 6% 2 6% 4 4 5% 5% 6% 9% 38%	2660
July	1st to 10th	Day	10% 5% 2 6% 4 6% 6% 5% 6% 11% 38%	4440
	11th to 20th	Day	12% 6% 2 6% 5% 4 5% 4 7% 10% 38%	4319
	21st to end	Day	10% 6% 2 8% 5% 6% 5% 5% 6% 8% 40%	4466
August	1st to 10th	Day	16% 7% 3 7% 5% 5% 5% 4 6% 9% 34%	4104
	11th to 20th	Day	15% 7% 3 8% 5% 6% 6% 5% 7% 9% 29%	4044
	21st to end	Day	12% 6% 2 6% 4 5% 5% 4 7% 10% 38%	4311
September	1st to 10th	Day	17% 7% 3 7% 4 4 4 4 5% 7% 37%	2280
	11th to 20th	Day	14% 7% 2 5% 5% 4 4 4 6% 8% 42%	2161
	21st to end	Day	20% 9% 3 8% 5% 5% 5% 3 5% 6% 30%	2052
October	1st to 10th	Day	20% 9% 3 8% 5% 4 4 4 5% 7% 31%	1900
	11th to 20th	Day	21% 13% 3 8% 5% 5% 5% 4 4 5% 28%	1900
	21st to end	Day	24% 18% 4 8% 4 5% 4 2 4 6% 21%	2090
November	1st to 10th	Day	14% 20% 3 7% 5% 4 4 4 6% 5% 29%	1800
	11th to 20th	Day	17% 24% 4 8% 5% 4 3 3 5% 5% 21%	1600
	21st to end	Day	17% 27% 7% 10% 4 3 4 4 4 6% 14%	1600
December	1st to 10th	Day	18% 31% 14% 13% 5% 3 3 2 2 2 7%	2600
	11th to 20th	Day	18% 23% 9% 18% 5% 3 3 2 3 3 12%	2986
	21st to end	Day	20% 25% 10% 14% 7% 4 3 2 3 4 10%	3960
January	1st to 10th	Night	12% 20% 10% 31% 9% 3 2 1 2 2 6%	6259
	11th to 20th	Night	8% 20% 12% 25% 9% 5% 4 2 3 3 8%	5859
	21st to end	Night	18% 18% 9% 17% 9% 4 4 2 3 4 11%	6490
February	1st to 10th	Night	15% 22% 5% 16% 9% 5% 4 2 3 3 15%	2600
	11th to 20th	Night	13% 17% 6% 17% 10% 7% 4 3 4 4 15%	2533
	21st to end	Night	16% 16% 5% 17% 7% 3 4 3 4 4 20%	1937
March	1st to 10th	Night	20% 16% 5% 10% 5% 4 3 3 3 5% 27%	3408
	11th to 20th	Night	16% 15% 9% 12% 6% 3 3 3 4 5% 25%	3479
	21st to end	Night	15% 12% 6% 11% 5% 4 4 3 4 4 32%	3817
April	1st to 10th	Night	16% 16% 5% 8% 4 4 4 3 4 6% 29%	1946
	11th to 20th	Night	18% 13% 2 6% 4 5% 4 3 5% 6% 34%	1862
	21st to end	Night	15% 12% 3 8% 5% 5% 5% 4 5% 6% 33%	1710
May	1st to 10th	Night	25% 10% 3 6% 4 4 4 3 4 6% 31%	2833
	11th to 20th	Night	16% 10% 3 7% 5% 4 5% 3 5% 7% 36%	2633
	21st to end	Night	14% 5% 2 5% 3 3 3 3 6% 9% 46%	2738
June	1st to 10th	Night	13% 7% 2 8% 4 5% 5% 4 6% 9% 36%	1520
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 7% 8% 40%	1520
	21st to end	Night	13% 6% 2 7% 5% 5% 5% 4 6% 8% 40%	1520
July	1st to 10th	Night	10% 7% 3 8% 5% 4 4 4 6% 8% 40%	2520
	11th to 20th	Night	13% 5% 2 5% 4 3 5% 4 6% 9% 44%	2638
	21st to end	Night	10% 5% 2 6% 5% 5% 6% 4 6% 7% 44%	3087
August	1st to 10th	Night	12% 9% 3 8% 4 4 4 4 7% 7% 38%	2825
	11th to 20th	Night	16% 9% 3 7% 5% 4 5% 4 6% 7% 35%	2785
	21st to end	Night	10% 5% 2 6% 4 5% 5% 4 5% 9% 44%	3311
September	1st to 10th	Night	14% 7% 2 6% 4 4 4 4 5% 7% 43%	1900
	11th to 20th	Night	13% 7% 2 5% 4 3 4 3 4 6% 48%	2016
	21st to end	Night	21% 8% 2 8% 5% 5% 6% 4 4 6% 32%	2126
October	1st to 10th	Night	19% 7% 3 7% 4 4 4 4 5% 6% 37%	2280
	11th to 20th	Night	22% 12% 3 7% 4 4 5% 3 5% 6% 29%	2280
	21st to end	Night	26% 14% 3 6% 4 4 4 3 4 5% 26%	2508
November	1st to 10th	Night	16% 17% 3 7% 4 3 3 3 4 6% 32%	2491
	11th to 20th	Night	17% 21% 4 9% 5% 5% 4 4 5% 5% 21%	2800
	21st to end	Night	17% 25% 7% 10% 5% 4 3 3 4 4 18%	2800
December	1st to 10th	Night	14% 26% 11% 15% 6% 5% 4 3 3 3 9%	4580
	11th to 20th	Night	18% 24% 11% 16% 5% 4 3 2 3 3 11%	5208
	21st to end	Night	20% 22% 9% 14% 7% 4 4 3 4 4 11%	6996

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	85% 3 5% 6% 2	3672
	11th to 20th	Day	83% 2 6% 6% 2	4060
	21st to end	Day	80% 2 7% 8% 3	4466
February	1st to 10th	Day	78% 3 7% 8% 4	1800
	11th to 20th	Day	76% 3 5% 11% 5%	1762
	21st to end	Day	67% 3 9% 14% 5% 2	1514
March	1st to 10th	Day	60% 3 10% 22% 5%	3435
	11th to 20th	Day	61% 3 15% 14% 5% 1	3480
	21st to end	Day	60% 4 6% 19% 10% 1	3815
April	1st to 10th	Day	57% 3 11% 17% 11%	2233
	11th to 20th	Day	53% 4 10% 21% 10% 2	2283
	21st to end	Day	55% 3 9% 18% 13% 2	2470
May	1st to 10th	Day	54% 3 10% 23% 8% 2	4120
	11th to 20th	Day	54% 4 13% 21% 7% 1	4262
	21st to end	Day	40% 4 15% 22% 15% 4	4837
June	1st to 10th	Day	45% 4 13% 23% 13% 1	2660
	11th to 20th	Day	45% 5% 14% 23% 13% 1	2660
	21st to end	Day	42% 5% 14% 25% 13% 1	2660
July	1st to 10th	Day	39% 6% 14% 25% 15% 1	4370
	11th to 20th	Day	40% 6% 13% 24% 17%	4244
	21st to end	Day	41% 6% 14% 23% 15% 1	4324
August	1st to 10th	Day	45% 6% 14% 23% 11%	4091
	11th to 20th	Day	48% 7% 15% 23% 6%	4083
	21st to end	Day	40% 6% 12% 31% 11% 1	4311
September	1st to 10th	Day	46% 5% 12% 23% 12% 1	2280
	11th to 20th	Day	40% 5% 13% 28% 15%	2161
	21st to end	Day	54% 4 10% 22% 9% 1	2052
October	1st to 10th	Day	44% 6% 14% 21% 14% 1	3160
	11th to 20th	Day	50% 5% 13% 16% 12% 3	3140
	21st to end	Day	51% 5% 15% 21% 8% 1	3428
November	1st to 10th	Day	56% 5% 10% 17% 10% 2	1800
	11th to 20th	Day	65% 3 10% 14% 6% 2	1600
	21st to end	Day	74% 3 9% 10% 3 1	1600
December	1st to 10th	Day	86% 3 5% 5% 1	2600
	11th to 20th	Day	80% 2 7% 9% 1	2986
	21st to end	Day	81% 2 9% 6% 1	3960
January	1st to 10th	Night	87% 2 5% 4 2	6259
	11th to 20th	Night	83% 2 8% 5% 2	5900
	21st to end	Night	78% 3 8% 8% 3	6490
February	1st to 10th	Night	76% 3 8% 10% 3	2600
	11th to 20th	Night	74% 3 7% 12% 4	2535
	21st to end	Night	68% 3 9% 13% 7% 1	1937
March	1st to 10th	Night	62% 3 9% 22% 5%	3418
	11th to 20th	Night	63% 3 11% 16% 7% 1	3480
	21st to end	Night	55% 5% 8% 18% 13% 2	3817
April	1st to 10th	Night	57% 4 11% 18% 10% 1	1946
	11th to 20th	Night	51% 4 11% 20% 12% 2	1862
	21st to end	Night	51% 5% 12% 18% 12% 3	1710
May	1st to 10th	Night	55% 4 8% 19% 10% 4	2840
	11th to 20th	Night	49% 4 16% 22% 8% 2	2634
	21st to end	Night	35% 5% 14% 26% 15% 5%	2739
June	1st to 10th	Night	42% 6% 12% 24% 14% 1	1520
	11th to 20th	Night	42% 5% 14% 23% 15% 2	1520
	21st to end	Night	42% 7% 12% 27% 12%	1520
July	1st to 10th	Night	41% 5% 13% 22% 16% 3	2480
	11th to 20th	Night	36% 5% 14% 28% 15% 1	2590
	21st to end	Night	37% 7% 14% 23% 18% 1	2988
August	1st to 10th	Night	43% 5% 12% 29% 9% 1	2814
	11th to 20th	Night	46% 7% 16% 25% 7%	2812
	21st to end	Night	36% 6% 15% 32% 10% 1	3311
September	1st to 10th	Night	41% 5% 12% 26% 13% 2	1900
	11th to 20th	Night	39% 3 13% 26% 18% 1	2016
	21st to end	Night	52% 5% 11% 20% 11% 1	2126
October	1st to 10th	Night	43% 5% 9% 22% 19% 1	3800
	11th to 20th	Night	49% 5% 13% 16% 14% 3	3779
	21st to end	Night	45% 4 15% 23% 12% 1	4120
November	1st to 10th	Night	53% 5% 10% 20% 10% 2	2491
	11th to 20th	Night	64% 4 10% 13% 6% 3	2800
	21st to end	Night	71% 3 10% 12% 3 1	2800
December	1st to 10th	Night	81% 4 8% 6% 1	4580
	11th to 20th	Night	79% 3 8% 9% 2	5208
	21st to end	Night	79% 4 8% 9% 1	6996

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	32% 25% 30% 10% 2	217
	11th to 20th	Day	35% 31% 24% 9% 1	300
	21st to end	Day	33% 28% 29% 8% 2	330
February	1st to 10th	Day	39% 24% 30% 7%	300
	11th to 20th	Day	37% 32% 26% 5%	300
	21st to end	Day	39% 22% 33% 6%	267
March	1st to 10th	Day	31% 23% 32% 11% 3	460
	11th to 20th	Day	30% 23% 34% 10% 2 1	460
	21st to end	Day	33% 22% 27% 13% 4	506
April	1st to 10th	Day	31% 20% 30% 13% 5% 1	460
	11th to 20th	Day	33% 19% 24% 14% 6% 3	452
	21st to end	Day	30% 17% 35% 13% 4 1	460
May	1st to 10th	Day	32% 15% 32% 14% 5% 2	463
	11th to 20th	Day	24% 14% 30% 25% 6% 2	487
	21st to end	Day	16% 13% 33% 24% 10% 5%	529
June	1st to 10th	Day	20% 14% 33% 22% 9% 2	490
	11th to 20th	Day	17% 11% 30% 26% 14% 2	490
	21st to end	Day	20% 12% 33% 24% 9% 2	490
July	1st to 10th	Day	14% 7% 30% 26% 17% 6%	485
	11th to 20th	Day	16% 8% 30% 24% 16% 5%	484
	21st to end	Day	11% 9% 36% 23% 16% 5%	532
August	1st to 10th	Day	13% 8% 28% 28% 16% 7%	486
	11th to 20th	Day	19% 7% 25% 27% 16% 6%	479
	21st to end	Day	16% 8% 27% 27% 15% 7%	539
September	1st to 10th	Day	18% 13% 23% 25% 16% 5%	490
	11th to 20th	Day	12% 6% 25% 26% 22% 9%	490
	21st to end	Day	24% 13% 29% 19% 11% 4	490
October	1st to 10th	Day	25% 10% 30% 19% 15% 2	490
	11th to 20th	Day	28% 19% 30% 17% 5% 2	490
	21st to end	Day	40% 14% 29% 13% 3	539
November	1st to 10th	Day	31% 22% 26% 15% 3 2	368
	11th to 20th	Day	40% 19% 30% 10% 2 1	200
	21st to end	Day	40% 23% 32% 6%	200
December	1st to 10th	Day	39% 26% 27% 7% 1 1	200
	11th to 20th	Day	39% 26% 28% 8% 1	200
	21st to end	Day	38% 21% 32% 8% 1	220
January	1st to 10th	Night	32% 27% 28% 10% 3	800
	11th to 20th	Night	32% 25% 29% 13% 2	800
	21st to end	Night	26% 27% 30% 15% 2	880
February	1st to 10th	Night	33% 25% 29% 14% 1	800
	11th to 20th	Night	28% 27% 31% 12% 2	783
	21st to end	Night	31% 25% 28% 13% 2	629
March	1st to 10th	Night	29% 20% 31% 16% 3	760
	11th to 20th	Night	31% 19% 27% 18% 4 1	760
	21st to end	Night	27% 17% 33% 18% 5% 1	836
April	1st to 10th	Night	26% 18% 32% 19% 4	760
	11th to 20th	Night	28% 14% 31% 19% 7% 1	738
	21st to end	Night	23% 12% 33% 26% 6%	570
May	1st to 10th	Night	24% 11% 25% 28% 10% 1	570
	11th to 20th	Night	18% 8% 30% 35% 7% 1	460
	21st to end	Night	16% 8% 27% 29% 18% 1	411
June	1st to 10th	Night	15% 8% 32% 31% 14% 1	380
	11th to 20th	Night	17% 8% 26% 35% 14%	380
	21st to end	Night	16% 8% 29% 34% 12%	380
July	1st to 10th	Night	10% 5% 22% 40% 19% 4	370
	11th to 20th	Night	15% 3 22% 35% 24% 2	434
	21st to end	Night	12% 5% 23% 33% 25% 1	624
August	1st to 10th	Night	13% 3 18% 41% 22% 3	567
	11th to 20th	Night	15% 4 18% 32% 28% 3	564
	21st to end	Night	15% 5% 21% 31% 24% 4	736
September	1st to 10th	Night	20% 7% 19% 30% 21% 3	760
	11th to 20th	Night	16% 6% 19% 28% 27% 4	760
	21st to end	Night	25% 10% 21% 25% 15% 3	760
October	1st to 10th	Night	23% 9% 28% 23% 15% 2	760
	11th to 20th	Night	33% 14% 26% 20% 6% 1	760
	21st to end	Night	37% 15% 28% 17% 3	836
November	1st to 10th	Night	31% 14% 26% 23% 7%	780
	11th to 20th	Night	34% 21% 26% 14% 5% 1	800
	21st to end	Night	34% 24% 27% 11% 4	800
December	1st to 10th	Night	37% 26% 25% 9% 3	800
	11th to 20th	Night	33% 27% 26% 13% 2	800
	21st to end	Night	34% 23% 30% 11% 2	880

Page generated at 2025-02-18 03:26:33. Version ac07

Copyright © 2025 Attilla Danko.