Wakefield
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wakefield clear sky chart from 2005-11-06 to 2026-07-31.

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% 5% 5% 5% 4 5% 7% 31%	138706
	Night	16% 12% 4 9% 5% 5% 4 3 5% 6% 30%	134308
Transparency	Day	35% 35% 7% 15% 6%	142186
	Night	37% 35% 7% 13% 7% 1	138917
Seeing	Day	25% 17% 31% 18% 7% 2	16601
	Night	23% 14% 28% 25% 9% 1	25636

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% 18% 6% 15% 6% 5% 4 4 4 5% 19%	4661
	11th to 20th	Day	10% 21% 7% 15% 7% 5% 4 3 5% 5% 18%	4650
	21st to end	Day	8% 15% 7% 16% 9% 8% 5% 3 4 5% 20%	5344
February	1st to 10th	Day	13% 16% 5% 14% 8% 5% 4 4 5% 5% 23%	1890
	11th to 20th	Day	11% 17% 6% 11% 6% 5% 4 3 5% 6% 26%	1843
	21st to end	Day	19% 13% 6% 10% 6% 5% 4 4 5% 4 24%	1725
March	1st to 10th	Day	19% 16% 4 11% 5% 4 4 3 4 5% 23%	4593
	11th to 20th	Day	12% 14% 5% 10% 5% 5% 4 4 5% 6% 29%	5090
	21st to end	Day	17% 12% 3 8% 6% 4 4 3 4 5% 35%	5885
April	1st to 10th	Day	22% 14% 3 7% 5% 4 3 3 3 6% 30%	2520
	11th to 20th	Day	23% 11% 3 6% 4 4 4 3 4 4 34%	2494
	21st to end	Day	21% 11% 3 8% 5% 4 4 3 3 5% 32%	2686
May	1st to 10th	Day	21% 10% 3 7% 5% 5% 5% 5% 6% 7% 26%	8237
	11th to 20th	Day	17% 8% 3 9% 5% 5% 5% 4 6% 8% 32%	8221
	21st to end	Day	21% 9% 3 7% 4 4 4 4 5% 6% 34%	9060
June	1st to 10th	Day	21% 9% 3 7% 5% 5% 5% 4 5% 7% 30%	2940
	11th to 20th	Day	15% 6% 3 6% 5% 5% 5% 5% 6% 8% 37%	2940
	21st to end	Day	19% 7% 3 6% 5% 5% 5% 5% 6% 8% 32%	2940
July	1st to 10th	Day	14% 6% 2 7% 5% 5% 6% 5% 7% 9% 33%	6500
	11th to 20th	Day	12% 6% 2 6% 4 4 5% 4 6% 7% 43%	6500
	21st to end	Day	10% 5% 2 5% 4 3 5% 4 6% 10% 45%	7066
August	1st to 10th	Day	14% 6% 3 8% 5% 5% 6% 4 6% 9% 36%	4500
	11th to 20th	Day	17% 7% 2 6% 4 4 4 4 7% 9% 36%	4144
	21st to end	Day	13% 5% 2 6% 4 5% 5% 4 7% 10% 39%	4312
September	1st to 10th	Day	14% 6% 2 5% 4 4 5% 4 6% 7% 43%	2400
	11th to 20th	Day	12% 6% 2 5% 5% 4 4 3 5% 7% 47%	2400
	21st to end	Day	18% 7% 2 7% 4 4 4 3 5% 7% 39%	2131
October	1st to 10th	Day	20% 8% 3 7% 5% 4 4 3 5% 6% 36%	2000
	11th to 20th	Day	23% 9% 3 8% 4 6% 4 4 4 8% 27%	2000
	21st to end	Day	25% 11% 3 8% 4 5% 5% 3 4 5% 27%	2040
November	1st to 10th	Day	16% 11% 3 7% 6% 5% 4 4 5% 7% 32%	1840
	11th to 20th	Day	18% 14% 5% 8% 6% 4 5% 3 5% 7% 24%	1680
	21st to end	Day	22% 16% 5% 11% 6% 5% 3 4 5% 4 19%	1680
December	1st to 10th	Day	21% 21% 6% 11% 5% 5% 4 4 5% 5% 13%	2680
	11th to 20th	Day	18% 16% 7% 11% 5% 4 4 3 3 3 24%	3066
	21st to end	Day	22% 18% 5% 11% 6% 5% 4 3 3 5% 19%	4048
January	1st to 10th	Night	13% 20% 8% 14% 6% 4 4 3 4 5% 18%	8234
	11th to 20th	Night	11% 19% 7% 15% 7% 6% 4 3 4 4 19%	8235
	21st to end	Night	9% 16% 6% 14% 8% 7% 5% 3 5% 5% 21%	8835
February	1st to 10th	Night	12% 15% 5% 12% 7% 6% 5% 4 5% 6% 25%	2730
	11th to 20th	Night	12% 14% 6% 12% 7% 5% 4 3 4 5% 28%	2663
	21st to end	Night	14% 14% 5% 9% 6% 5% 5% 4 5% 6% 27%	2081
March	1st to 10th	Night	22% 15% 4 9% 5% 4 4 3 3 4 28%	5466
	11th to 20th	Night	12% 13% 5% 9% 5% 5% 5% 4 6% 8% 28%	5089
	21st to end	Night	18% 12% 3 9% 5% 4 3 3 5% 5% 33%	5289
April	1st to 10th	Night	21% 11% 4 8% 4 4 3 4 4 6% 31%	2100
	11th to 20th	Night	18% 10% 4 8% 5% 4 4 3 4 6% 35%	2075
	21st to end	Night	21% 10% 3 7% 4 3 3 3 5% 6% 34%	1952
May	1st to 10th	Night	20% 10% 3 8% 5% 5% 5% 4 6% 7% 26%	4660
	11th to 20th	Night	16% 8% 3 7% 5% 4 5% 4 5% 7% 37%	4639
	21st to end	Night	20% 8% 3 7% 5% 5% 5% 4 5% 6% 34%	5114
June	1st to 10th	Night	17% 7% 2 6% 6% 5% 5% 5% 6% 8% 35%	1680
	11th to 20th	Night	13% 7% 2 6% 4 4 4 3 6% 8% 42%	1680
	21st to end	Night	18% 7% 2 5% 5% 6% 5% 4 6% 7% 36%	1680
July	1st to 10th	Night	14% 8% 3 8% 5% 5% 5% 4 6% 8% 35%	3680
	11th to 20th	Night	13% 6% 2 6% 4 4 4 4 6% 8% 43%	3680
	21st to end	Night	9% 6% 2 5% 4 5% 4 4 6% 8% 47%	4006
August	1st to 10th	Night	13% 7% 3 8% 4 4 4 4 7% 8% 39%	2646
	11th to 20th	Night	16% 7% 2 6% 4 3 4 4 6% 7% 41%	2875
	21st to end	Night	14% 5% 2 7% 4 4 5% 4 6% 7% 41%	3581
September	1st to 10th	Night	11% 6% 1 5% 5% 3 5% 4 5% 7% 47%	2000
	11th to 20th	Night	14% 6% 1 5% 3 3 4 4 5% 6% 50%	2000
	21st to end	Night	18% 7% 2 6% 4 3 3 2 5% 5% 44%	2265
October	1st to 10th	Night	18% 7% 2 6% 4 4 4 3 5% 6% 41%	2400
	11th to 20th	Night	20% 8% 3 8% 6% 5% 5% 4 5% 6% 31%	2400
	21st to end	Night	23% 10% 3 8% 5% 4 4 3 5% 5% 29%	2800
November	1st to 10th	Night	19% 11% 3 7% 5% 4 5% 3 5% 6% 31%	2675
	11th to 20th	Night	19% 13% 4 8% 5% 5% 5% 4 4 5% 28%	2940
	21st to end	Night	20% 15% 4 11% 5% 5% 5% 3 4 6% 22%	2940
December	1st to 10th	Night	18% 18% 6% 13% 6% 5% 5% 4 5% 6% 15%	4720
	11th to 20th	Night	23% 14% 6% 11% 5% 3 3 2 3 4 25%	5348
	21st to end	Night	24% 19% 4 10% 4 4 3 2 3 4 21%	7150

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	54% 22% 7% 12% 4	4662
	11th to 20th	Day	58% 21% 5% 8% 8%	4680
	21st to end	Day	55% 24% 6% 8% 6%	5344
February	1st to 10th	Day	27% 59% 3 7% 3 1	1890
	11th to 20th	Day	26% 57% 4 8% 4	1852
	21st to end	Day	27% 58% 4 4 6% 1	1725
March	1st to 10th	Day	48% 29% 5% 7% 9% 2	4596
	11th to 20th	Day	40% 29% 11% 10% 8% 1	5090
	21st to end	Day	39% 29% 3 13% 14% 1	5885
April	1st to 10th	Day	24% 59% 3 6% 6% 1	2520
	11th to 20th	Day	24% 59% 2 9% 5% 1	2494
	21st to end	Day	23% 59% 3 8% 6% 1	2686
May	1st to 10th	Day	44% 24% 6% 17% 7% 1	8249
	11th to 20th	Day	40% 25% 11% 18% 6%	8225
	21st to end	Day	42% 23% 8% 18% 9%	9061
June	1st to 10th	Day	21% 59% 3 10% 6% 1	2940
	11th to 20th	Day	20% 60% 5% 10% 5% 1	2940
	21st to end	Day	20% 58% 5% 12% 5%	2940
July	1st to 10th	Day	35% 27% 11% 20% 7%	6430
	11th to 20th	Day	28% 27% 10% 27% 8%	6425
	21st to end	Day	24% 26% 12% 29% 8%	6868
August	1st to 10th	Day	29% 37% 12% 16% 6%	4486
	11th to 20th	Day	30% 37% 9% 20% 4	4183
	21st to end	Day	25% 37% 11% 19% 8%	4312
September	1st to 10th	Day	16% 58% 8% 12% 5%	2400
	11th to 20th	Day	14% 57% 5% 17% 6%	2400
	21st to end	Day	16% 57% 6% 13% 8%	2131
October	1st to 10th	Day	32% 36% 7% 21% 4	3260
	11th to 20th	Day	29% 37% 9% 18% 7%	3240
	21st to end	Day	33% 37% 13% 14% 3	3278
November	1st to 10th	Day	30% 53% 6% 8% 3 1	1840
	11th to 20th	Day	27% 54% 5% 10% 4	1680
	21st to end	Day	33% 55% 4 3 4	1680
December	1st to 10th	Day	50% 35% 7% 7% 1	2680
	11th to 20th	Day	48% 32% 5% 10% 6%	3066
	21st to end	Day	52% 26% 5% 14% 4	4048
January	1st to 10th	Night	56% 21% 9% 10% 4	8234
	11th to 20th	Night	56% 21% 7% 11% 5%	8280
	21st to end	Night	54% 23% 5% 9% 9%	8835
February	1st to 10th	Night	25% 58% 4 9% 4	2730
	11th to 20th	Night	25% 57% 3 11% 4	2665
	21st to end	Night	24% 59% 3 7% 6%	2081
March	1st to 10th	Night	46% 28% 5% 9% 9% 3	5476
	11th to 20th	Night	39% 30% 12% 11% 6% 2	5090
	21st to end	Night	41% 28% 5% 15% 9% 2	5289
April	1st to 10th	Night	23% 59% 3 8% 5% 1	2100
	11th to 20th	Night	22% 59% 2 10% 7%	2075
	21st to end	Night	20% 58% 4 8% 8% 1	1952
May	1st to 10th	Night	46% 25% 7% 16% 5% 1	4666
	11th to 20th	Night	38% 25% 10% 17% 9%	4640
	21st to end	Night	43% 24% 7% 16% 10%	5115
June	1st to 10th	Night	18% 60% 3 12% 6% 1	1680
	11th to 20th	Night	17% 60% 4 11% 8% 1	1680
	21st to end	Night	20% 58% 4 12% 6%	1680
July	1st to 10th	Night	37% 28% 12% 15% 8%	3640
	11th to 20th	Night	29% 27% 10% 26% 8%	3632
	21st to end	Night	25% 27% 10% 28% 10%	3889
August	1st to 10th	Night	27% 38% 10% 18% 6%	2636
	11th to 20th	Night	29% 37% 10% 19% 4	2902
	21st to end	Night	27% 37% 9% 17% 8% 2	3581
September	1st to 10th	Night	14% 58% 7% 16% 6%	2000
	11th to 20th	Night	14% 57% 5% 17% 6% 1	2000
	21st to end	Night	16% 57% 4 15% 8%	2265
October	1st to 10th	Night	25% 35% 9% 22% 9%	3920
	11th to 20th	Night	28% 36% 11% 18% 7%	3899
	21st to end	Night	31% 37% 12% 13% 6%	4512
November	1st to 10th	Night	28% 53% 7% 9% 3	2675
	11th to 20th	Night	27% 54% 5% 10% 4	2940
	21st to end	Night	30% 54% 5% 7% 3	2940
December	1st to 10th	Night	46% 36% 8% 9% 2	4720
	11th to 20th	Night	47% 30% 4 10% 9% 1	5348
	21st to end	Night	52% 25% 3 11% 9%	7150

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	27% 20% 33% 15% 4	220
	11th to 20th	Day	29% 20% 37% 11% 2 1	220
	21st to end	Day	21% 22% 36% 17% 4	283
February	1st to 10th	Day	32% 23% 32% 12% 2	330
	11th to 20th	Day	28% 31% 35% 6% 1	330
	21st to end	Day	31% 23% 31% 13% 1	441
March	1st to 10th	Day	28% 22% 33% 13% 4	540
	11th to 20th	Day	30% 23% 30% 13% 3 1	540
	21st to end	Day	34% 21% 29% 13% 4 1	594
April	1st to 10th	Day	37% 22% 25% 13% 4	540
	11th to 20th	Day	37% 20% 22% 13% 7% 1	532
	21st to end	Day	31% 22% 29% 12% 5% 1	540
May	1st to 10th	Day	27% 19% 31% 15% 6% 2	543
	11th to 20th	Day	22% 19% 32% 19% 7% 2	567
	21st to end	Day	27% 16% 31% 19% 7% 2	617
June	1st to 10th	Day	26% 13% 33% 19% 7% 1	570
	11th to 20th	Day	20% 16% 32% 22% 8% 2	570
	21st to end	Day	22% 15% 32% 20% 8% 2	570
July	1st to 10th	Day	13% 12% 35% 29% 9% 2	565
	11th to 20th	Day	15% 13% 34% 26% 11% 2	564
	21st to end	Day	15% 10% 34% 28% 10% 4	616
August	1st to 10th	Day	13% 10% 29% 32% 13% 3	526
	11th to 20th	Day	18% 6% 26% 31% 13% 7%	519
	21st to end	Day	16% 13% 30% 25% 13% 5%	583
September	1st to 10th	Day	17% 14% 29% 23% 11% 6%	530
	11th to 20th	Day	13% 10% 25% 21% 20% 10%	530
	21st to end	Day	22% 13% 29% 20% 13% 4	530
October	1st to 10th	Day	23% 18% 24% 23% 9% 3	530
	11th to 20th	Day	28% 17% 34% 14% 6% 1	530
	21st to end	Day	32% 16% 29% 19% 4	495
November	1st to 10th	Day	29% 18% 29% 17% 5% 1	414
	11th to 20th	Day	25% 26% 32% 11% 5%	220
	21st to end	Day	33% 24% 30% 10% 2 2	220
December	1st to 10th	Day	33% 13% 40% 12% 1	220
	11th to 20th	Day	28% 26% 36% 8% 2	220
	21st to end	Day	31% 22% 35% 9% 2 1	242
January	1st to 10th	Night	27% 16% 34% 20% 3	840
	11th to 20th	Night	31% 17% 27% 20% 5%	840
	21st to end	Night	19% 16% 36% 23% 5% 1	924
February	1st to 10th	Night	20% 21% 31% 24% 3	840
	11th to 20th	Night	21% 21% 37% 17% 3	823
	21st to end	Night	25% 17% 30% 23% 5%	692
March	1st to 10th	Night	27% 17% 32% 20% 4	840
	11th to 20th	Night	25% 20% 31% 19% 5%	840
	21st to end	Night	27% 17% 29% 21% 6%	924
April	1st to 10th	Night	30% 16% 27% 23% 4	840
	11th to 20th	Night	27% 18% 28% 20% 6%	831
	21st to end	Night	27% 16% 27% 23% 7%	692
May	1st to 10th	Night	25% 13% 27% 27% 8% 1	420
	11th to 20th	Night	22% 11% 28% 30% 9%	414
	21st to end	Night	19% 9% 36% 26% 9%	455
June	1st to 10th	Night	19% 9% 29% 34% 9%	420
	11th to 20th	Night	17% 10% 27% 33% 13% 1	420
	21st to end	Night	20% 8% 22% 37% 13%	420
July	1st to 10th	Night	10% 6% 30% 38% 16%	410
	11th to 20th	Night	13% 5% 24% 40% 17%	408
	21st to end	Night	10% 6% 26% 40% 16% 2	458
August	1st to 10th	Night	12% 5% 20% 42% 21% 1	432
	11th to 20th	Night	12% 6% 19% 37% 23% 3	594
	21st to end	Night	15% 6% 25% 33% 19% 2	875
September	1st to 10th	Night	15% 7% 29% 29% 19% 1	800
	11th to 20th	Night	16% 7% 21% 30% 22% 4	800
	21st to end	Night	21% 7% 27% 25% 18% 2	800
October	1st to 10th	Night	22% 12% 26% 24% 15% 1	800
	11th to 20th	Night	25% 14% 29% 24% 7% 1	800
	21st to end	Night	28% 14% 29% 24% 5%	880
November	1st to 10th	Night	28% 15% 26% 24% 7% 1	820
	11th to 20th	Night	27% 17% 31% 16% 9%	840
	21st to end	Night	32% 17% 24% 21% 5%	840
December	1st to 10th	Night	30% 17% 29% 20% 4	840
	11th to 20th	Night	28% 20% 28% 19% 5%	840
	21st to end	Night	34% 17% 29% 16% 4	924

Page generated at 2026-07-28 03:25:22. Version ac07

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