New Liskeard
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the New Liskeard clear sky chart from 2005-11-06 to 2025-01-07.

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% 4 9% 6% 5% 5% 4 5% 6% 29%	105079
	Night	15% 13% 5% 10% 6% 5% 5% 4 5% 6% 27%	104018
Transparency	Day	54% 7% 12% 19% 7% 1	108587
	Night	58% 6% 11% 16% 7% 1	108599
Seeing	Day	21% 14% 30% 23% 10% 3	15319
	Night	23% 11% 30% 26% 8% 1	24441

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	13% 20% 7% 13% 6% 7% 5% 4 5% 5% 12%	2250
	11th to 20th	Day	10% 13% 7% 18% 10% 7% 7% 4 4 5% 16%	2210
	21st to end	Day	13% 18% 9% 15% 8% 5% 4 3 5% 5% 14%	3032
February	1st to 10th	Day	7% 15% 6% 15% 9% 8% 5% 5% 5% 6% 19%	1710
	11th to 20th	Day	10% 17% 5% 12% 8% 6% 6% 4 6% 5% 21%	1663
	21st to end	Day	12% 17% 4 11% 8% 6% 5% 4 5% 5% 23%	1413
March	1st to 10th	Day	18% 14% 5% 10% 5% 4 4 4 5% 6% 26%	3379
	11th to 20th	Day	9% 17% 6% 17% 6% 4 4 3 4 4 26%	3480
	21st to end	Day	12% 14% 6% 11% 7% 6% 5% 3 4 4 29%	3815
April	1st to 10th	Day	18% 14% 4 9% 6% 4 5% 3 5% 6% 25%	2264
	11th to 20th	Day	20% 12% 3 8% 5% 4 4 3 5% 6% 31%	2418
	21st to end	Day	21% 11% 4 7% 4 4 3 3 5% 6% 32%	2470
May	1st to 10th	Day	18% 10% 3 7% 5% 4 4 4 6% 7% 33%	4300
	11th to 20th	Day	16% 8% 3 8% 5% 5% 4 4 5% 6% 35%	4398
	21st to end	Day	17% 8% 3 6% 4 4 4 3 5% 8% 38%	4923
June	1st to 10th	Day	18% 9% 2 7% 6% 4 5% 4 6% 8% 29%	2850
	11th to 20th	Day	13% 7% 2 6% 6% 5% 5% 5% 7% 8% 36%	2850
	21st to end	Day	17% 8% 3 7% 6% 6% 5% 4 5% 7% 32%	2850
July	1st to 10th	Day	17% 7% 3 6% 5% 5% 5% 5% 7% 9% 32%	4760
	11th to 20th	Day	14% 5% 2 6% 5% 5% 5% 5% 6% 8% 38%	4760
	21st to end	Day	13% 6% 2 6% 5% 4 5% 4 6% 9% 40%	4915
August	1st to 10th	Day	13% 6% 2 8% 5% 5% 6% 5% 7% 8% 36%	4106
	11th to 20th	Day	19% 6% 2 6% 4 4 5% 4 6% 6% 38%	4044
	21st to end	Day	12% 6% 3 7% 5% 4 5% 4 5% 8% 41%	4468
September	1st to 10th	Day	16% 7% 2 6% 5% 5% 5% 4 5% 7% 37%	2280
	11th to 20th	Day	18% 8% 2 7% 4 4 4 3 5% 7% 37%	2180
	21st to end	Day	21% 9% 2 7% 5% 4 5% 3 4 6% 33%	2047
October	1st to 10th	Day	19% 11% 4 7% 5% 5% 5% 4 5% 6% 31%	1900
	11th to 20th	Day	22% 16% 4 8% 6% 5% 4 4 4 4 22%	1900
	21st to end	Day	24% 16% 5% 11% 5% 5% 4 4 5% 5% 17%	1998
November	1st to 10th	Day	19% 15% 5% 11% 6% 3 4 3 4 6% 24%	1566
	11th to 20th	Day	18% 15% 5% 15% 7% 5% 5% 4 5% 5% 17%	1600
	21st to end	Day	21% 20% 6% 13% 7% 6% 6% 3 3 5% 11%	1600
December	1st to 10th	Day	12% 25% 9% 16% 7% 5% 5% 3 4 3 10%	2583
	11th to 20th	Day	14% 17% 6% 13% 9% 6% 4 3 4 5% 21%	2621
	21st to end	Day	18% 19% 6% 17% 7% 5% 4 5% 4 4 11%	3476
January	1st to 10th	Night	12% 17% 7% 15% 8% 6% 5% 4 5% 5% 14%	4839
	11th to 20th	Night	10% 14% 5% 15% 8% 7% 7% 5% 5% 5% 17%	4760
	21st to end	Night	12% 18% 10% 13% 8% 8% 5% 3 5% 4 13%	4621
February	1st to 10th	Night	11% 15% 5% 12% 10% 7% 6% 4 5% 6% 19%	2470
	11th to 20th	Night	11% 17% 6% 11% 9% 6% 5% 3 4 4 24%	2403
	21st to end	Night	12% 15% 5% 13% 8% 6% 5% 4 5% 6% 22%	2041
March	1st to 10th	Night	13% 16% 5% 9% 5% 5% 5% 3 4 4 32%	3457
	11th to 20th	Night	12% 20% 5% 13% 6% 5% 3 3 4 5% 23%	3479
	21st to end	Night	13% 11% 5% 12% 6% 5% 4 3 5% 5% 31%	3817
April	1st to 10th	Night	19% 16% 4 9% 5% 3 3 3 5% 4 29%	1915
	11th to 20th	Night	19% 11% 4 8% 5% 4 3 4 5% 5% 33%	1727
	21st to end	Night	18% 10% 3 8% 5% 3 4 3 5% 6% 35%	1710
May	1st to 10th	Night	16% 10% 4 8% 5% 6% 5% 3 5% 6% 32%	2641
	11th to 20th	Night	16% 7% 2 7% 5% 5% 4 3 5% 8% 37%	2495
	21st to end	Night	15% 7% 2 6% 5% 4 5% 4 6% 8% 38%	2652
June	1st to 10th	Night	17% 8% 3 8% 5% 4 6% 5% 6% 6% 32%	1330
	11th to 20th	Night	18% 5% 2 5% 4 4 4 4 5% 8% 42%	1330
	21st to end	Night	16% 6% 2 7% 5% 5% 4 3 6% 9% 36%	1330
July	1st to 10th	Night	15% 7% 2 6% 4 5% 4 4 5% 8% 40%	2210
	11th to 20th	Night	15% 5% 2 7% 5% 5% 4 5% 6% 7% 38%	2210
	21st to end	Night	15% 5% 2 5% 4 4 4 4 6% 7% 44%	2638
August	1st to 10th	Night	9% 5% 2 8% 6% 5% 5% 4 5% 9% 40%	2820
	11th to 20th	Night	16% 6% 3 6% 4 4 4 5% 5% 8% 40%	2785
	21st to end	Night	14% 6% 2 7% 3 4 4 3 5% 6% 44%	3156
September	1st to 10th	Night	16% 5% 2 6% 4 4 5% 2 6% 7% 42%	1900
	11th to 20th	Night	17% 7% 2 6% 4 4 4 2 5% 6% 44%	1995
	21st to end	Night	20% 7% 2 7% 3 3 3 3 5% 7% 39%	2133
October	1st to 10th	Night	20% 11% 3 7% 4 4 4 3 5% 7% 32%	2280
	11th to 20th	Night	23% 15% 3 8% 5% 5% 5% 4 5% 5% 23%	2280
	21st to end	Night	21% 16% 4 10% 5% 5% 4 3 5% 5% 23%	2594
November	1st to 10th	Night	17% 15% 4 8% 6% 5% 5% 3 5% 6% 26%	2732
	11th to 20th	Night	16% 16% 5% 12% 7% 5% 5% 3 4 5% 19%	2800
	21st to end	Night	20% 20% 6% 11% 6% 4 5% 4 5% 5% 14%	2800
December	1st to 10th	Night	14% 23% 10% 16% 8% 5% 5% 3 4 4 10%	4580
	11th to 20th	Night	15% 17% 5% 13% 9% 6% 5% 4 4 4 18%	5586
	21st to end	Night	20% 19% 6% 15% 6% 5% 4 3 3 4 16%	7502

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	73% 8% 11% 7% 1	2251
	11th to 20th	Day	69% 7% 9% 12% 3	2210
	21st to end	Day	71% 6% 9% 10% 4	3032
February	1st to 10th	Day	64% 7% 9% 12% 6%	1710
	11th to 20th	Day	63% 6% 10% 12% 8%	1672
	21st to end	Day	62% 7% 8% 15% 8%	1413
March	1st to 10th	Day	59% 7% 10% 18% 7% 1	3382
	11th to 20th	Day	61% 7% 9% 15% 8%	3480
	21st to end	Day	57% 6% 8% 18% 10% 2	3815
April	1st to 10th	Day	58% 6% 11% 16% 8% 1	2264
	11th to 20th	Day	53% 7% 8% 22% 9% 1	2418
	21st to end	Day	53% 6% 8% 16% 14% 2	2470
May	1st to 10th	Day	47% 8% 13% 21% 9% 1	4312
	11th to 20th	Day	46% 9% 14% 21% 9% 1	4402
	21st to end	Day	43% 8% 13% 19% 16% 1	4923
June	1st to 10th	Day	51% 8% 12% 20% 9% 1	2850
	11th to 20th	Day	43% 8% 13% 23% 12% 1	2850
	21st to end	Day	50% 8% 11% 20% 10% 1	2850
July	1st to 10th	Day	47% 7% 16% 24% 6%	4686
	11th to 20th	Day	41% 7% 17% 27% 8%	4679
	21st to end	Day	40% 7% 14% 31% 7%	4759
August	1st to 10th	Day	43% 8% 16% 26% 6%	4092
	11th to 20th	Day	44% 8% 15% 24% 8% 1	4083
	21st to end	Day	42% 7% 13% 29% 8% 2	4468
September	1st to 10th	Day	46% 9% 15% 22% 8%	2280
	11th to 20th	Day	46% 8% 17% 23% 6%	2180
	21st to end	Day	53% 7% 13% 21% 6%	2047
October	1st to 10th	Day	55% 5% 11% 23% 5%	3160
	11th to 20th	Day	58% 6% 11% 18% 7%	3140
	21st to end	Day	66% 6% 14% 9% 5%	3263
November	1st to 10th	Day	64% 6% 14% 13% 4	1566
	11th to 20th	Day	70% 7% 9% 10% 4	1600
	21st to end	Day	81% 4 7% 6% 2	1600
December	1st to 10th	Day	82% 4 7% 5% 2	2583
	11th to 20th	Day	69% 4 9% 16% 2	2621
	21st to end	Day	77% 4 7% 9% 3	3476
January	1st to 10th	Night	70% 8% 12% 8% 2	4839
	11th to 20th	Night	67% 8% 10% 12% 4	4760
	21st to end	Night	73% 7% 7% 9% 4	4621
February	1st to 10th	Night	64% 6% 10% 12% 7%	2470
	11th to 20th	Night	64% 5% 11% 14% 5%	2405
	21st to end	Night	62% 6% 9% 14% 8% 1	2041
March	1st to 10th	Night	55% 5% 11% 16% 11% 2	3467
	11th to 20th	Night	63% 6% 10% 13% 6% 1	3480
	21st to end	Night	54% 5% 9% 16% 12% 3	3817
April	1st to 10th	Night	58% 4 10% 15% 12% 1	1915
	11th to 20th	Night	52% 5% 9% 20% 13% 2	1727
	21st to end	Night	51% 5% 11% 15% 17% 2	1710
May	1st to 10th	Night	50% 9% 9% 18% 12% 1	2648
	11th to 20th	Night	44% 6% 13% 23% 13% 1	2496
	21st to end	Night	43% 7% 13% 20% 14% 3	2653
June	1st to 10th	Night	48% 8% 12% 20% 10% 2	1330
	11th to 20th	Night	39% 8% 12% 23% 15% 2	1330
	21st to end	Night	45% 7% 13% 21% 12% 1	1330
July	1st to 10th	Night	43% 7% 14% 25% 11%	2175
	11th to 20th	Night	45% 6% 16% 24% 8% 1	2168
	21st to end	Night	39% 7% 14% 25% 14%	2554
August	1st to 10th	Night	40% 7% 16% 30% 8%	2810
	11th to 20th	Night	42% 7% 17% 28% 5%	2812
	21st to end	Night	42% 7% 15% 25% 10% 2	3156
September	1st to 10th	Night	41% 8% 18% 23% 9% 2	1900
	11th to 20th	Night	43% 6% 18% 25% 8%	1995
	21st to end	Night	44% 9% 15% 24% 8%	2133
October	1st to 10th	Night	51% 6% 12% 22% 10%	3800
	11th to 20th	Night	58% 5% 13% 20% 4	3779
	21st to end	Night	59% 7% 16% 12% 5%	4279
November	1st to 10th	Night	59% 7% 14% 16% 4	2732
	11th to 20th	Night	68% 8% 10% 10% 4	2800
	21st to end	Night	74% 7% 10% 7% 1	2800
December	1st to 10th	Night	81% 4 6% 7% 2	4580
	11th to 20th	Night	70% 5% 9% 11% 6%	5585
	21st to end	Night	75% 4 6% 12% 3	7502

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% 16% 39% 17% 5% 1	192
	11th to 20th	Day	16% 18% 36% 21% 7% 2	180
	21st to end	Day	19% 12% 34% 23% 10% 1	288
February	1st to 10th	Day	19% 24% 33% 19% 4	270
	11th to 20th	Day	21% 21% 35% 19% 4	270
	21st to end	Day	28% 27% 31% 14%	225
March	1st to 10th	Day	18% 17% 38% 21% 7%	427
	11th to 20th	Day	17% 20% 33% 23% 7% 1	460
	21st to end	Day	24% 15% 35% 18% 6% 1	506
April	1st to 10th	Day	23% 16% 31% 20% 8% 1	460
	11th to 20th	Day	27% 17% 24% 21% 7% 3	452
	21st to end	Day	27% 18% 26% 17% 9% 3	460
May	1st to 10th	Day	25% 11% 30% 21% 11% 2	463
	11th to 20th	Day	22% 13% 29% 22% 11% 3	487
	21st to end	Day	19% 15% 31% 24% 9% 2	576
June	1st to 10th	Day	18% 13% 33% 26% 7% 2	680
	11th to 20th	Day	17% 13% 28% 26% 12% 3	680
	21st to end	Day	19% 10% 27% 29% 13% 2	680
July	1st to 10th	Day	14% 11% 31% 29% 13% 2	671
	11th to 20th	Day	16% 10% 29% 27% 16% 3	668
	21st to end	Day	12% 10% 26% 31% 16% 5%	594
August	1st to 10th	Day	16% 9% 28% 26% 16% 5%	486
	11th to 20th	Day	16% 7% 21% 28% 17% 11%	479
	21st to end	Day	18% 11% 27% 23% 13% 8%	539
September	1st to 10th	Day	19% 10% 27% 26% 14% 4	490
	11th to 20th	Day	18% 8% 24% 31% 13% 6%	490
	21st to end	Day	24% 11% 26% 20% 15% 3	490
October	1st to 10th	Day	27% 13% 27% 20% 11% 2	490
	11th to 20th	Day	28% 20% 32% 14% 4 1	490
	21st to end	Day	32% 17% 32% 15% 2 1	456
November	1st to 10th	Day	33% 20% 34% 11% 3	200
	11th to 20th	Day	28% 17% 34% 18% 4 1	200
	21st to end	Day	32% 20% 33% 11% 4 1	200
December	1st to 10th	Day	24% 16% 35% 20% 7%	200
	11th to 20th	Day	26% 15% 35% 17% 7% 2	200
	21st to end	Day	24% 17% 33% 19% 6% 1	220
January	1st to 10th	Night	25% 13% 32% 24% 6%	981
	11th to 20th	Night	25% 13% 31% 25% 6%	950
	21st to end	Night	18% 9% 30% 30% 12% 1	867
February	1st to 10th	Night	18% 14% 35% 26% 7%	760
	11th to 20th	Night	21% 11% 38% 25% 5%	743
	21st to end	Night	21% 15% 35% 23% 5%	628
March	1st to 10th	Night	20% 15% 35% 24% 5% 1	760
	11th to 20th	Night	20% 16% 34% 23% 6% 1	760
	21st to end	Night	21% 13% 35% 26% 5% 1	836
April	1st to 10th	Night	26% 13% 29% 26% 5% 1	760
	11th to 20th	Night	25% 14% 28% 25% 8%	603
	21st to end	Night	23% 12% 28% 30% 6% 1	570
May	1st to 10th	Night	20% 9% 30% 34% 7%	456
	11th to 20th	Night	21% 8% 30% 31% 9% 1	374
	21st to end	Night	20% 7% 29% 37% 5%	411
June	1st to 10th	Night	17% 9% 32% 36% 6%	380
	11th to 20th	Night	21% 8% 27% 33% 11%	380
	21st to end	Night	16% 6% 28% 35% 14% 1	380
July	1st to 10th	Night	13% 4 34% 38% 10% 1	370
	11th to 20th	Night	16% 6% 24% 40% 13%	368
	21st to end	Night	13% 5% 25% 41% 14% 1	416
August	1st to 10th	Night	15% 5% 25% 36% 17% 2	562
	11th to 20th	Night	17% 5% 22% 35% 20% 2	564
	21st to end	Night	19% 8% 27% 29% 16% 2	646
September	1st to 10th	Night	18% 6% 30% 30% 15% 1	760
	11th to 20th	Night	20% 8% 26% 26% 17% 2	760
	21st to end	Night	24% 8% 22% 31% 14% 1	760
October	1st to 10th	Night	26% 8% 32% 25% 9% 1	760
	11th to 20th	Night	31% 13% 29% 20% 7% 1	760
	21st to end	Night	32% 12% 30% 21% 4 1	836
November	1st to 10th	Night	26% 14% 35% 19% 6% 1	780
	11th to 20th	Night	25% 16% 34% 18% 6% 1	800
	21st to end	Night	33% 14% 29% 19% 4	800
December	1st to 10th	Night	29% 14% 32% 18% 7% 1	800
	11th to 20th	Night	27% 14% 31% 22% 5% 1	1000
	21st to end	Night	28% 15% 26% 24% 7% 1	1100

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