Palgrave Conservation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Palgrave Conservation Area clear sky chart from 2005-11-06 to 2025-07-21.

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	14% 11% 4 9% 6% 5% 5% 4 5% 7% 30%	120894
	Night	14% 11% 4 9% 6% 5% 5% 4 5% 6% 31%	118194
Transparency	Day	51% 7% 12% 19% 10% 1	124528
	Night	50% 8% 12% 19% 10% 1	122721
Seeing	Day	21% 19% 31% 18% 8% 3	15690
	Night	20% 17% 31% 22% 9% 1	24674

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% 12% 5% 18% 8% 6% 5% 4 6% 5% 19%	3597
	11th to 20th	Day	10% 18% 7% 18% 11% 7% 5% 3 4 5% 11%	3952
	21st to end	Day	16% 18% 7% 16% 6% 5% 5% 4 4 5% 14%	4466
February	1st to 10th	Day	13% 17% 4 14% 9% 7% 6% 5% 4 4 17%	1800
	11th to 20th	Day	11% 15% 7% 15% 8% 5% 4 3 5% 5% 20%	1753
	21st to end	Day	15% 18% 5% 10% 5% 5% 5% 3 5% 5% 23%	1545
March	1st to 10th	Day	16% 12% 6% 10% 7% 4 3 3 4 5% 29%	4930
	11th to 20th	Day	10% 14% 5% 10% 6% 5% 5% 3 5% 7% 30%	4980
	21st to end	Day	15% 15% 5% 9% 5% 4 4 3 4 4 32%	5465
April	1st to 10th	Day	15% 16% 4 9% 5% 4 4 3 5% 6% 29%	2345
	11th to 20th	Day	17% 12% 3 7% 4 4 4 3 4 6% 35%	2482
	21st to end	Day	19% 11% 4 8% 4 4 4 3 5% 7% 33%	2600
May	1st to 10th	Day	18% 9% 4 7% 4 4 4 3 5% 7% 35%	5888
	11th to 20th	Day	15% 10% 3 9% 5% 5% 4 4 5% 7% 33%	6244
	21st to end	Day	18% 7% 2 6% 4 5% 4 3 5% 7% 38%	6949
June	1st to 10th	Day	15% 6% 3 5% 5% 5% 5% 4 7% 9% 36%	2800
	11th to 20th	Day	11% 6% 2 7% 4 4 6% 4 7% 9% 40%	2883
	21st to end	Day	14% 6% 2 6% 5% 4 5% 4 7% 8% 38%	3000
July	1st to 10th	Day	11% 5% 3 7% 6% 5% 5% 5% 7% 10% 37%	4822
	11th to 20th	Day	9% 6% 2 5% 5% 4 5% 5% 7% 9% 43%	4580
	21st to end	Day	9% 6% 2 7% 5% 5% 6% 5% 7% 8% 40%	4474
August	1st to 10th	Day	14% 8% 2 7% 5% 5% 5% 4 7% 8% 35%	4104
	11th to 20th	Day	11% 8% 3 8% 6% 5% 6% 4 8% 9% 32%	4044
	21st to end	Day	10% 7% 2 6% 4 5% 5% 4 7% 8% 41%	4386
September	1st to 10th	Day	13% 8% 3 7% 5% 5% 5% 3 4 8% 39%	2280
	11th to 20th	Day	11% 6% 2 7% 5% 5% 4 4 5% 9% 43%	2142
	21st to end	Day	15% 7% 3 8% 7% 5% 5% 4 6% 8% 33%	2066
October	1st to 10th	Day	19% 9% 3 8% 4 5% 4 3 5% 6% 32%	1900
	11th to 20th	Day	19% 11% 4 9% 6% 4 5% 4 4 6% 28%	1900
	21st to end	Day	25% 16% 4 8% 5% 4 3 4 4 6% 21%	2090
November	1st to 10th	Day	12% 14% 4 9% 5% 6% 5% 4 6% 8% 28%	1681
	11th to 20th	Day	12% 15% 5% 11% 7% 5% 5% 4 6% 7% 23%	1600
	21st to end	Day	15% 18% 7% 11% 7% 5% 4 5% 5% 6% 17%	1600
December	1st to 10th	Day	17% 20% 7% 12% 7% 6% 5% 3 5% 5% 12%	2600
	11th to 20th	Day	18% 22% 5% 12% 5% 4 5% 3 4 5% 18%	2986
	21st to end	Day	23% 18% 7% 17% 6% 5% 4 3 4 4 10%	3960
January	1st to 10th	Night	13% 13% 5% 13% 9% 8% 6% 3 5% 6% 20%	6349
	11th to 20th	Night	10% 14% 7% 17% 13% 8% 6% 4 5% 5% 11%	5929
	21st to end	Night	13% 14% 6% 12% 8% 6% 5% 4 5% 6% 19%	6490
February	1st to 10th	Night	13% 15% 5% 11% 9% 5% 4 4 5% 6% 23%	2600
	11th to 20th	Night	11% 14% 5% 12% 8% 7% 6% 3 5% 6% 23%	2533
	21st to end	Night	11% 12% 5% 11% 7% 6% 5% 4 6% 6% 26%	2083
March	1st to 10th	Night	14% 11% 5% 10% 6% 5% 5% 4 5% 6% 28%	4908
	11th to 20th	Night	8% 9% 4 8% 5% 5% 6% 5% 7% 8% 34%	4979
	21st to end	Night	16% 10% 4 7% 5% 4 5% 3 5% 5% 36%	5467
April	1st to 10th	Night	17% 13% 3 9% 6% 5% 4 3 4 6% 30%	2053
	11th to 20th	Night	17% 9% 2 5% 5% 4 5% 4 5% 6% 37%	1886
	21st to end	Night	14% 12% 3 7% 4 4 5% 4 6% 6% 35%	1800
May	1st to 10th	Night	19% 8% 2 7% 4 4 4 3 5% 6% 36%	4053
	11th to 20th	Night	13% 7% 3 7% 5% 4 4 4 6% 7% 41%	3649
	21st to end	Night	16% 6% 3 5% 3 3 3 3 5% 7% 46%	3926
June	1st to 10th	Night	13% 6% 2 5% 4 6% 4 4 6% 9% 42%	1600
	11th to 20th	Night	9% 4 2 7% 4 4 5% 5% 7% 9% 43%	1509
	21st to end	Night	12% 5% 2 6% 4 4 4 4 5% 8% 47%	1400
July	1st to 10th	Night	5% 5% 2 6% 4 4 5% 4 6% 7% 51%	2344
	11th to 20th	Night	10% 4 2 4 4 3 4 3 5% 7% 53%	2600
	21st to end	Night	6% 6% 2 5% 4 4 5% 4 7% 7% 51%	3076
August	1st to 10th	Night	10% 6% 3 6% 3 4 4 3 6% 7% 49%	2825
	11th to 20th	Night	11% 7% 2 5% 3 3 4 4 5% 8% 48%	2785
	21st to end	Night	11% 6% 2 5% 4 3 5% 3 6% 7% 48%	3238
September	1st to 10th	Night	9% 5% 2 6% 4 4 4 4 7% 6% 49%	1900
	11th to 20th	Night	11% 4 2 4 3 3 3 4 5% 7% 54%	2033
	21st to end	Night	15% 7% 3 6% 5% 4 4 3 5% 7% 41%	2114
October	1st to 10th	Night	17% 6% 3 8% 5% 5% 4 3 6% 7% 38%	2280
	11th to 20th	Night	17% 10% 3 7% 5% 5% 4 4 6% 5% 34%	2280
	21st to end	Night	20% 12% 3 9% 5% 5% 5% 5% 5% 6% 26%	2508
November	1st to 10th	Night	15% 10% 3 8% 5% 5% 5% 4 6% 6% 34%	2613
	11th to 20th	Night	15% 13% 4 10% 6% 5% 5% 4 6% 7% 27%	2800
	21st to end	Night	16% 15% 5% 11% 6% 5% 5% 4 5% 7% 22%	2800
December	1st to 10th	Night	16% 16% 6% 12% 7% 6% 6% 4 7% 6% 14%	4580
	11th to 20th	Night	13% 19% 7% 14% 6% 5% 5% 4 5% 5% 18%	5208
	21st to end	Night	22% 19% 7% 16% 5% 5% 4 3 4 4 12%	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	62% 9% 11% 13% 6%	3598
	11th to 20th	Day	73% 7% 8% 8% 3	3986
	21st to end	Day	70% 7% 10% 9% 5%	4466
February	1st to 10th	Day	68% 7% 7% 14% 3 1	1800
	11th to 20th	Day	63% 8% 10% 12% 6% 1	1762
	21st to end	Day	62% 7% 8% 14% 7% 1	1545
March	1st to 10th	Day	56% 6% 13% 13% 12%	4933
	11th to 20th	Day	51% 6% 14% 19% 7% 2	4980
	21st to end	Day	54% 6% 8% 18% 13% 2	5465
April	1st to 10th	Day	56% 6% 9% 18% 10% 1	2345
	11th to 20th	Day	49% 5% 9% 22% 14% 1	2482
	21st to end	Day	51% 6% 11% 18% 12% 2	2600
May	1st to 10th	Day	47% 6% 13% 18% 11% 5%	5897
	11th to 20th	Day	49% 8% 10% 16% 16% 1	6248
	21st to end	Day	44% 6% 11% 21% 15% 2	6949
June	1st to 10th	Day	43% 8% 11% 21% 16% 1	2800
	11th to 20th	Day	38% 7% 15% 24% 15% 1	2883
	21st to end	Day	41% 7% 14% 24% 13% 1	3000
July	1st to 10th	Day	40% 8% 15% 21% 15% 1	4750
	11th to 20th	Day	34% 8% 12% 34% 11% 1	4505
	21st to end	Day	38% 9% 13% 23% 17% 1	4331
August	1st to 10th	Day	44% 7% 14% 23% 11% 1	4091
	11th to 20th	Day	44% 7% 16% 23% 9%	4083
	21st to end	Day	38% 7% 15% 30% 10% 1	4386
September	1st to 10th	Day	43% 7% 13% 25% 10% 2	2280
	11th to 20th	Day	38% 6% 13% 29% 14%	2142
	21st to end	Day	48% 6% 13% 23% 8%	2066
October	1st to 10th	Day	43% 8% 13% 25% 11% 1	3160
	11th to 20th	Day	43% 7% 14% 21% 14%	3140
	21st to end	Day	58% 6% 13% 17% 6%	3428
November	1st to 10th	Day	52% 9% 12% 19% 8%	1681
	11th to 20th	Day	58% 8% 13% 14% 7%	1600
	21st to end	Day	66% 9% 12% 11% 3	1600
December	1st to 10th	Day	73% 6% 13% 6% 2	2600
	11th to 20th	Day	68% 7% 10% 8% 6%	2986
	21st to end	Day	77% 6% 6% 6% 5%	3960
January	1st to 10th	Night	59% 12% 10% 15% 4	6349
	11th to 20th	Night	70% 10% 8% 10% 3	5970
	21st to end	Night	60% 9% 11% 10% 9% 1	6490
February	1st to 10th	Night	59% 8% 11% 17% 5%	2600
	11th to 20th	Night	60% 7% 10% 16% 7%	2535
	21st to end	Night	54% 8% 13% 16% 8%	2083
March	1st to 10th	Night	51% 8% 12% 17% 10% 2	4918
	11th to 20th	Night	42% 8% 19% 21% 9% 1	4980
	21st to end	Night	47% 6% 10% 20% 15% 2	5467
April	1st to 10th	Night	55% 4 10% 17% 12% 1	2053
	11th to 20th	Night	46% 6% 10% 21% 16% 1	1886
	21st to end	Night	47% 6% 12% 17% 16% 2	1800
May	1st to 10th	Night	47% 5% 12% 15% 14% 6%	4060
	11th to 20th	Night	41% 7% 12% 23% 14% 2	3650
	21st to end	Night	38% 7% 13% 26% 15% 2	3927
June	1st to 10th	Night	38% 7% 12% 24% 18% 2	1600
	11th to 20th	Night	35% 8% 13% 24% 19% 1	1509
	21st to end	Night	35% 8% 13% 27% 16% 1	1400
July	1st to 10th	Night	30% 7% 15% 25% 20% 3	2307
	11th to 20th	Night	30% 6% 12% 35% 17% 1	2552
	21st to end	Night	30% 9% 14% 30% 15% 2	2978
August	1st to 10th	Night	35% 5% 13% 30% 15% 2	2814
	11th to 20th	Night	34% 6% 16% 30% 13% 1	2812
	21st to end	Night	33% 7% 14% 32% 13% 1	3238
September	1st to 10th	Night	32% 8% 15% 29% 14% 1	1900
	11th to 20th	Night	29% 6% 12% 34% 18%	2033
	21st to end	Night	44% 6% 13% 27% 10% 1	2114
October	1st to 10th	Night	34% 7% 9% 27% 21% 1	3800
	11th to 20th	Night	43% 7% 12% 24% 14% 1	3779
	21st to end	Night	45% 8% 15% 23% 8%	4120
November	1st to 10th	Night	47% 8% 12% 22% 10% 1	2613
	11th to 20th	Night	53% 8% 14% 15% 8% 1	2800
	21st to end	Night	59% 10% 15% 13% 2 1	2800
December	1st to 10th	Night	66% 9% 13% 9% 2	4580
	11th to 20th	Night	65% 8% 9% 11% 6%	5208
	21st to end	Night	74% 8% 7% 8% 3	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	24% 25% 35% 14% 3 1	200
	11th to 20th	Day	24% 30% 29% 11% 4 1	283
	21st to end	Day	30% 25% 31% 11% 2	330
February	1st to 10th	Day	35% 31% 23% 8% 3	300
	11th to 20th	Day	30% 32% 32% 5% 1	300
	21st to end	Day	37% 33% 24% 5%	249
March	1st to 10th	Day	25% 26% 32% 14% 4	498
	11th to 20th	Day	26% 22% 35% 12% 4	500
	21st to end	Day	33% 22% 29% 12% 4 1	550
April	1st to 10th	Day	28% 25% 32% 11% 5%	500
	11th to 20th	Day	34% 21% 24% 12% 7% 2	492
	21st to end	Day	28% 20% 32% 13% 5% 2	500
May	1st to 10th	Day	23% 18% 33% 17% 7% 2	503
	11th to 20th	Day	20% 18% 31% 20% 8% 3	527
	21st to end	Day	17% 17% 30% 24% 9% 4	573
June	1st to 10th	Day	17% 18% 35% 21% 8% 2	530
	11th to 20th	Day	16% 14% 35% 23% 10% 2	613
	21st to end	Day	17% 15% 37% 22% 6% 3	730
July	1st to 10th	Day	12% 10% 34% 27% 14% 3	674
	11th to 20th	Day	11% 10% 33% 27% 13% 6%	524
	21st to end	Day	11% 8% 38% 26% 12% 5%	532
August	1st to 10th	Day	11% 8% 29% 29% 15% 8%	486
	11th to 20th	Day	10% 9% 30% 25% 18% 8%	479
	21st to end	Day	15% 11% 31% 23% 15% 6%	539
September	1st to 10th	Day	14% 12% 30% 24% 13% 8%	490
	11th to 20th	Day	10% 11% 25% 23% 19% 12%	490
	21st to end	Day	16% 17% 27% 22% 13% 5%	490
October	1st to 10th	Day	24% 17% 25% 20% 10% 4	490
	11th to 20th	Day	23% 22% 34% 14% 6% 1	490
	21st to end	Day	32% 23% 29% 13% 3	539
November	1st to 10th	Day	26% 26% 27% 17% 3 1	269
	11th to 20th	Day	30% 23% 31% 12% 5% 1	200
	21st to end	Day	26% 25% 39% 10% 1	200
December	1st to 10th	Day	33% 26% 30% 11% 1	200
	11th to 20th	Day	32% 29% 28% 10% 1 1	200
	21st to end	Day	30% 30% 30% 6% 3	220
January	1st to 10th	Night	23% 30% 30% 13% 4	800
	11th to 20th	Night	26% 23% 31% 17% 3	800
	21st to end	Night	18% 22% 35% 19% 5%	880
February	1st to 10th	Night	23% 27% 33% 15% 1	800
	11th to 20th	Night	23% 25% 36% 13% 3	783
	21st to end	Night	22% 26% 35% 15% 2	660
March	1st to 10th	Night	22% 24% 34% 17% 3	800
	11th to 20th	Night	23% 24% 32% 16% 5%	800
	21st to end	Night	23% 20% 32% 19% 6%	880
April	1st to 10th	Night	26% 20% 34% 19% 2	800
	11th to 20th	Night	22% 19% 33% 18% 8% 1	702
	21st to end	Night	20% 16% 32% 24% 7%	600
May	1st to 10th	Night	19% 10% 31% 29% 11% 2	600
	11th to 20th	Night	18% 9% 33% 30% 9% 1	429
	21st to end	Night	11% 10% 35% 31% 13%	433
June	1st to 10th	Night	13% 10% 36% 31% 10%	400
	11th to 20th	Night	11% 11% 31% 35% 13%	400
	21st to end	Night	14% 7% 32% 34% 14%	400
July	1st to 10th	Night	7% 4 29% 41% 17% 2	390
	11th to 20th	Night	10% 9% 27% 35% 19% 1	388
	21st to end	Night	8% 5% 31% 38% 17% 1	613
August	1st to 10th	Night	10% 3 26% 37% 22% 2	567
	11th to 20th	Night	7% 5% 24% 39% 22% 2	564
	21st to end	Night	14% 5% 30% 28% 21% 2	689
September	1st to 10th	Night	11% 9% 29% 28% 18% 5%	760
	11th to 20th	Night	12% 8% 24% 28% 22% 5%	760
	21st to end	Night	19% 10% 23% 28% 16% 4	760
October	1st to 10th	Night	19% 12% 32% 21% 14% 2	760
	11th to 20th	Night	24% 17% 31% 20% 8% 1	760
	21st to end	Night	26% 21% 30% 19% 4	836
November	1st to 10th	Night	23% 18% 30% 21% 7% 1	780
	11th to 20th	Night	22% 25% 28% 19% 5% 1	800
	21st to end	Night	25% 23% 31% 18% 4	800
December	1st to 10th	Night	28% 24% 31% 13% 3	800
	11th to 20th	Night	22% 28% 32% 15% 3	800
	21st to end	Night	31% 21% 30% 15% 3	880

Page generated at 2025-07-18 01:09:59. Version ac07

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