Stone Tavern Farm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Stone Tavern Farm clear sky chart from 2005-11-06 to 2024-01-12.

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% 11% 5% 8% 6% 4 5% 5% 5% 7% 30%	74749
	Night	15% 12% 5% 8% 6% 3 5% 4 5% 6% 30%	74967
Transparency	Day	53% 7% 11% 17% 10% 1	74454
	Night	54% 7% 11% 17% 10% 1	74796
Seeing	Day	26% 20% 28% 16% 7% 3	13687
	Night	25% 20% 25% 21% 8% 1	22936

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	10% 12% 11% 11% 8% 3 5% 5% 5% 6% 23%	1517
	11th to 20th	Day	12% 16% 6% 13% 11% 3 6% 5% 4 4 20%	1454
	21st to end	Day	8% 13% 8% 14% 9% 5% 5% 4 5% 4 24%	1701
February	1st to 10th	Day	14% 15% 7% 12% 12% 4 5% 4 4 5% 18%	1620
	11th to 20th	Day	10% 12% 7% 13% 9% 4 5% 5% 5% 6% 25%	1691
	21st to end	Day	16% 15% 5% 11% 9% 3 4 5% 5% 4 23%	1480
March	1st to 10th	Day	12% 13% 6% 11% 8% 3 5% 5% 4 6% 29%	1797
	11th to 20th	Day	13% 15% 7% 9% 6% 3 4 3 5% 5% 28%	1926
	21st to end	Day	18% 12% 6% 9% 6% 2 4 3 4 6% 30%	2334
April	1st to 10th	Day	14% 15% 6% 8% 6% 3 5% 4 5% 5% 30%	2160
	11th to 20th	Day	16% 11% 3 7% 6% 3 5% 5% 4 6% 34%	2134
	21st to end	Day	20% 14% 4 8% 5% 3 4 3 4 6% 30%	2186
May	1st to 10th	Day	23% 12% 3 6% 5% 3 4 5% 5% 6% 28%	2420
	11th to 20th	Day	18% 9% 4 5% 5% 3 4 5% 6% 6% 34%	2478
	21st to end	Day	14% 7% 3 6% 7% 3 6% 6% 5% 8% 36%	2725
June	1st to 10th	Day	19% 8% 3 7% 6% 4 5% 5% 6% 9% 29%	2520
	11th to 20th	Day	18% 7% 3 6% 5% 3 6% 6% 7% 9% 29%	2520
	21st to end	Day	19% 7% 3 6% 6% 4 5% 5% 6% 8% 30%	2520
July	1st to 10th	Day	14% 6% 4 7% 6% 4 6% 5% 7% 9% 32%	2520
	11th to 20th	Day	11% 6% 3 6% 6% 4 6% 6% 8% 9% 34%	2520
	21st to end	Day	14% 7% 3 6% 7% 4 6% 5% 7% 8% 32%	2744
August	1st to 10th	Day	13% 7% 3 7% 7% 4 6% 6% 7% 9% 32%	2428
	11th to 20th	Day	16% 6% 3 7% 7% 4 6% 7% 7% 9% 28%	2153
	21st to end	Day	15% 5% 3 6% 6% 4 6% 6% 7% 8% 34%	2376
September	1st to 10th	Day	17% 6% 3 7% 6% 3 4 4 5% 8% 37%	2160
	11th to 20th	Day	15% 8% 3 5% 5% 3 4 4 5% 7% 43%	2111
	21st to end	Day	16% 6% 3 6% 5% 3 5% 5% 5% 8% 37%	1980
October	1st to 10th	Day	20% 9% 4 7% 6% 4 4 4 4 5% 32%	1829
	11th to 20th	Day	15% 12% 3 6% 5% 3 4 6% 6% 6% 34%	1800
	21st to end	Day	22% 17% 4 7% 5% 3 4 4 5% 5% 25%	1838
November	1st to 10th	Day	14% 13% 4 6% 5% 3 4 4 5% 7% 36%	1671
	11th to 20th	Day	15% 17% 5% 9% 6% 4 4 4 4 3 29%	1710
	21st to end	Day	15% 17% 6% 7% 6% 4 6% 4 4 6% 26%	1528
December	1st to 10th	Day	14% 20% 8% 13% 6% 3 5% 3 4 5% 18%	1520
	11th to 20th	Day	17% 17% 10% 10% 7% 3 3 3 3 4 24%	1906
	21st to end	Day	17% 18% 10% 12% 6% 3 4 4 5% 5% 16%	2772
January	1st to 10th	Night	12% 13% 8% 13% 7% 4 6% 5% 4 6% 24%	2649
	11th to 20th	Night	13% 15% 8% 13% 9% 4 5% 4 4 5% 20%	2546
	21st to end	Night	9% 12% 9% 12% 9% 5% 6% 5% 5% 7% 22%	2654
February	1st to 10th	Night	12% 14% 8% 12% 9% 5% 6% 5% 5% 5% 20%	2340
	11th to 20th	Night	10% 13% 8% 12% 10% 5% 6% 6% 5% 6% 20%	2155
	21st to end	Night	17% 11% 6% 11% 8% 4 5% 5% 4 5% 24%	1776
March	1st to 10th	Night	13% 12% 7% 13% 7% 3 4 4 4 5% 27%	2150
	11th to 20th	Night	13% 13% 7% 11% 9% 4 4 4 3 6% 27%	2029
	21st to end	Night	16% 12% 5% 7% 6% 3 4 4 4 6% 33%	2021
April	1st to 10th	Night	14% 15% 7% 8% 6% 4 4 5% 4 7% 27%	1800
	11th to 20th	Night	16% 14% 3 5% 6% 3 3 4 4 6% 36%	1775
	21st to end	Night	20% 13% 5% 5% 4 3 3 4 4 6% 33%	1772
May	1st to 10th	Night	20% 15% 3 6% 5% 3 3 4 4 5% 31%	1555
	11th to 20th	Night	14% 8% 4 8% 5% 3 5% 5% 5% 8% 35%	1415
	21st to end	Night	13% 7% 3 6% 5% 3 5% 5% 5% 8% 40%	1550
June	1st to 10th	Night	16% 7% 3 6% 5% 3 4 4 6% 8% 38%	1440
	11th to 20th	Night	18% 7% 3 5% 5% 2 4 4 6% 9% 38%	1440
	21st to end	Night	12% 6% 2 4 5% 4 6% 5% 6% 8% 42%	1440
July	1st to 10th	Night	12% 6% 2 5% 5% 3 5% 5% 7% 8% 42%	1440
	11th to 20th	Night	12% 5% 2 5% 6% 3 6% 5% 7% 9% 41%	1440
	21st to end	Night	12% 5% 3 5% 6% 4 4 5% 6% 8% 42%	1574
August	1st to 10th	Night	11% 6% 3 6% 5% 3 5% 5% 5% 9% 42%	1507
	11th to 20th	Night	13% 8% 3 7% 6% 3 6% 5% 6% 7% 37%	1727
	21st to end	Night	16% 6% 2 5% 4 3 4 4 5% 8% 42%	1980
September	1st to 10th	Night	15% 7% 3 5% 6% 3 4 4 5% 6% 42%	1800
	11th to 20th	Night	15% 6% 2 5% 4 2 3 3 4 7% 48%	1849
	21st to end	Night	16% 7% 2 6% 6% 3 4 4 4 6% 41%	1980
October	1st to 10th	Night	20% 10% 3 5% 4 3 5% 5% 5% 6% 34%	2128
	11th to 20th	Night	18% 10% 3 7% 6% 3 4 4 5% 6% 36%	2160
	21st to end	Night	22% 15% 3 7% 5% 3 3 4 5% 7% 25%	2516
November	1st to 10th	Night	12% 15% 4 7% 5% 3 4 4 5% 5% 37%	2407
	11th to 20th	Night	16% 15% 5% 7% 6% 3 4 5% 4 7% 27%	2470
	21st to end	Night	12% 13% 7% 9% 6% 4 6% 4 5% 7% 27%	2650
December	1st to 10th	Night	15% 18% 8% 12% 6% 3 5% 4 5% 5% 18%	2660
	11th to 20th	Night	17% 15% 7% 11% 7% 3 4 4 4 5% 22%	3288
	21st to end	Night	19% 16% 8% 13% 7% 3 4 4 4 5% 18%	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	60% 6% 10% 16% 7% 1	1518
	11th to 20th	Day	67% 7% 7% 10% 6% 3	1454
	21st to end	Day	62% 5% 10% 13% 8% 2	1701
February	1st to 10th	Day	68% 6% 9% 11% 5% 1	1620
	11th to 20th	Day	59% 6% 9% 16% 9% 1	1700
	21st to end	Day	61% 6% 9% 15% 8%	1480
March	1st to 10th	Day	56% 7% 11% 16% 9% 1	1800
	11th to 20th	Day	59% 5% 8% 16% 11% 2	1926
	21st to end	Day	55% 6% 7% 14% 14% 3	2334
April	1st to 10th	Day	57% 6% 7% 20% 9% 2	2160
	11th to 20th	Day	50% 8% 10% 18% 13% 1	2134
	21st to end	Day	56% 5% 9% 17% 11% 3	2186
May	1st to 10th	Day	57% 7% 7% 18% 9% 2	2420
	11th to 20th	Day	49% 8% 9% 21% 11% 2	2482
	21st to end	Day	46% 9% 15% 19% 8% 2	2725
June	1st to 10th	Day	51% 8% 14% 16% 10%	2520
	11th to 20th	Day	49% 8% 15% 18% 9% 1	2520
	21st to end	Day	50% 9% 13% 19% 8%	2520
July	1st to 10th	Day	47% 10% 12% 19% 11% 1	2450
	11th to 20th	Day	42% 10% 17% 22% 9%	2445
	21st to end	Day	47% 10% 13% 19% 10% 1	2591
August	1st to 10th	Day	47% 10% 13% 21% 10% 1	2414
	11th to 20th	Day	49% 11% 14% 21% 5%	2153
	21st to end	Day	44% 9% 13% 23% 11% 1	2376
September	1st to 10th	Day	45% 7% 13% 23% 11% 1	2160
	11th to 20th	Day	41% 6% 10% 22% 20% 1	2111
	21st to end	Day	44% 7% 12% 21% 14% 2	1980
October	1st to 10th	Day	53% 7% 9% 17% 12% 2	1829
	11th to 20th	Day	48% 9% 11% 21% 10% 1	1800
	21st to end	Day	61% 6% 10% 12% 9% 2	1838
November	1st to 10th	Day	48% 6% 12% 20% 13% 2	1671
	11th to 20th	Day	59% 6% 9% 15% 10% 2	1710
	21st to end	Day	58% 7% 12% 16% 6% 1	1528
December	1st to 10th	Day	69% 5% 9% 10% 5% 1	1520
	11th to 20th	Day	66% 4 12% 14% 4	1906
	21st to end	Day	70% 7% 7% 10% 7%	2772
January	1st to 10th	Night	60% 7% 11% 12% 9% 1	2649
	11th to 20th	Night	66% 6% 10% 9% 6% 2	2546
	21st to end	Night	60% 7% 9% 13% 8% 2	2654
February	1st to 10th	Night	64% 8% 9% 12% 7% 1	2340
	11th to 20th	Night	63% 8% 9% 12% 7% 1	2157
	21st to end	Night	60% 7% 9% 15% 8% 2	1776
March	1st to 10th	Night	59% 5% 10% 16% 9% 1	2160
	11th to 20th	Night	60% 5% 10% 15% 9% 1	2030
	21st to end	Night	52% 5% 10% 17% 14% 3	2021
April	1st to 10th	Night	57% 7% 10% 17% 8% 1	1800
	11th to 20th	Night	50% 7% 11% 19% 13%	1775
	21st to end	Night	52% 8% 8% 19% 10% 3	1772
May	1st to 10th	Night	56% 5% 9% 15% 13% 2	1555
	11th to 20th	Night	48% 7% 9% 21% 12% 2	1416
	21st to end	Night	41% 10% 16% 22% 10% 1	1551
June	1st to 10th	Night	45% 7% 12% 24% 12% 1	1440
	11th to 20th	Night	43% 8% 17% 23% 9%	1440
	21st to end	Night	38% 10% 16% 25% 10% 1	1440
July	1st to 10th	Night	37% 9% 17% 22% 12% 2	1400
	11th to 20th	Night	37% 9% 16% 28% 9%	1392
	21st to end	Night	38% 10% 16% 22% 13% 1	1486
August	1st to 10th	Night	39% 10% 15% 25% 10% 1	1497
	11th to 20th	Night	44% 9% 16% 22% 8%	1727
	21st to end	Night	39% 8% 14% 26% 13% 1	1980
September	1st to 10th	Night	41% 8% 14% 25% 12% 1	1800
	11th to 20th	Night	37% 6% 11% 24% 22% 1	1849
	21st to end	Night	45% 6% 9% 23% 15% 1	1980
October	1st to 10th	Night	51% 8% 11% 18% 11% 1	2128
	11th to 20th	Night	48% 8% 14% 19% 9% 1	2160
	21st to end	Night	58% 7% 11% 15% 8% 1	2516
November	1st to 10th	Night	49% 7% 10% 18% 14% 3	2407
	11th to 20th	Night	55% 7% 11% 16% 9% 3	2470
	21st to end	Night	55% 8% 14% 17% 6%	2650
December	1st to 10th	Night	67% 7% 10% 12% 4	2660
	11th to 20th	Night	65% 5% 10% 12% 7%	3288
	21st to end	Night	69% 6% 8% 11% 6%	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	32% 28% 25% 11% 3 1	180
	11th to 20th	Day	39% 28% 23% 8% 1 1	164
	21st to end	Day	29% 31% 29% 8% 3	228
February	1st to 10th	Day	43% 34% 20% 3	240
	11th to 20th	Day	38% 34% 19% 7% 1	359
	21st to end	Day	40% 25% 25% 9% 1	346
March	1st to 10th	Day	32% 28% 28% 10% 2	420
	11th to 20th	Day	36% 25% 25% 10% 3	420
	21st to end	Day	34% 27% 22% 10% 5% 2	462
April	1st to 10th	Day	34% 28% 21% 13% 4	420
	11th to 20th	Day	29% 25% 26% 12% 6% 2	412
	21st to end	Day	32% 23% 28% 10% 4 2	420
May	1st to 10th	Day	36% 19% 27% 9% 6% 4	423
	11th to 20th	Day	22% 21% 33% 17% 6% 2	447
	21st to end	Day	20% 12% 33% 20% 11% 4	485
June	1st to 10th	Day	22% 21% 31% 16% 8% 2	450
	11th to 20th	Day	20% 19% 28% 24% 7% 2	450
	21st to end	Day	22% 18% 32% 19% 7% 2	450
July	1st to 10th	Day	14% 12% 32% 25% 13% 3	445
	11th to 20th	Day	11% 11% 37% 27% 12% 2	444
	21st to end	Day	15% 12% 39% 23% 9% 2	488
August	1st to 10th	Day	10% 15% 30% 23% 16% 6%	446
	11th to 20th	Day	16% 12% 30% 23% 11% 7%	439
	21st to end	Day	15% 14% 30% 22% 12% 7%	495
September	1st to 10th	Day	21% 13% 23% 23% 14% 6%	450
	11th to 20th	Day	16% 14% 25% 22% 12% 11%	450
	21st to end	Day	19% 17% 28% 21% 10% 6%	450
October	1st to 10th	Day	26% 17% 26% 14% 13% 4	450
	11th to 20th	Day	25% 21% 27% 20% 6% 1	450
	21st to end	Day	32% 22% 26% 16% 4	423
November	1st to 10th	Day	28% 19% 23% 19% 9% 1	365
	11th to 20th	Day	37% 24% 21% 13% 5% 1	370
	21st to end	Day	37% 23% 29% 10% 1	188
December	1st to 10th	Day	37% 28% 23% 8% 4	180
	11th to 20th	Day	38% 27% 28% 6% 1	180
	21st to end	Day	37% 28% 26% 7% 1 1	198
January	1st to 10th	Night	28% 29% 29% 11% 2	760
	11th to 20th	Night	29% 27% 26% 15% 3	728
	21st to end	Night	23% 32% 28% 15% 2	792
February	1st to 10th	Night	32% 24% 32% 11% 1	720
	11th to 20th	Night	29% 30% 28% 12% 1	703
	21st to end	Night	35% 25% 27% 11% 2	592
March	1st to 10th	Night	29% 28% 27% 14% 2	720
	11th to 20th	Night	30% 28% 24% 15% 3	720
	21st to end	Night	27% 26% 25% 16% 6% 1	792
April	1st to 10th	Night	27% 25% 27% 18% 3	720
	11th to 20th	Night	27% 22% 26% 18% 7%	711
	21st to end	Night	30% 20% 23% 20% 7%	692
May	1st to 10th	Night	29% 15% 24% 23% 8% 1	475
	11th to 20th	Night	20% 15% 33% 27% 5% 1	354
	21st to end	Night	16% 9% 29% 30% 15% 1	389
June	1st to 10th	Night	18% 14% 24% 31% 14%	360
	11th to 20th	Night	19% 11% 20% 37% 13%	360
	21st to end	Night	15% 8% 26% 39% 13% 1	360
July	1st to 10th	Night	14% 9% 22% 38% 15% 1	350
	11th to 20th	Night	12% 5% 26% 36% 20% 1	348
	21st to end	Night	11% 7% 23% 43% 15% 1	394
August	1st to 10th	Night	12% 7% 24% 33% 22% 1	433
	11th to 20th	Night	15% 7% 18% 37% 20% 3	663
	21st to end	Night	17% 8% 20% 31% 23% 2	792
September	1st to 10th	Night	17% 8% 27% 29% 16% 3	720
	11th to 20th	Night	20% 10% 23% 24% 18% 6%	720
	21st to end	Night	20% 13% 24% 26% 15% 3	720
October	1st to 10th	Night	26% 16% 20% 23% 13% 2	720
	11th to 20th	Night	24% 17% 26% 26% 7% 1	720
	21st to end	Night	32% 22% 23% 20% 3	792
November	1st to 10th	Night	24% 21% 27% 21% 7%	740
	11th to 20th	Night	29% 25% 24% 15% 5% 2	760
	21st to end	Night	25% 28% 25% 17% 4 1	760
December	1st to 10th	Night	31% 29% 24% 12% 4	760
	11th to 20th	Night	32% 26% 24% 15% 2	760
	21st to end	Night	32% 31% 23% 13% 2	836

Page generated at 2024-01-09 16:24:22. Version ac07

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