Tiplady Farms Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tiplady Farms Observatory clear sky chart from 2005-11-06 to 2024-11-05.

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	18% 10% 3 8% 5% 4 4 4 5% 7% 32%	101370
	Night	19% 11% 4 8% 5% 4 4 3 5% 6% 31%	97684
Transparency	Day	52% 5% 12% 20% 10% 1	104868
	Night	55% 5% 11% 19% 9% 1	102262
Seeing	Day	25% 17% 29% 19% 8% 2	14810
	Night	25% 15% 27% 25% 8% 1	23803

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	16% 17% 6% 11% 6% 4 4 3 4 4 25%	2517
	11th to 20th	Day	15% 16% 7% 12% 9% 5% 3 3 4 4 22%	2520
	21st to end	Day	18% 20% 6% 11% 5% 4 4 2 4 4 22%	2781
February	1st to 10th	Day	15% 15% 5% 10% 8% 5% 4 4 5% 5% 23%	1710
	11th to 20th	Day	14% 16% 6% 12% 5% 5% 3 3 4 5% 26%	1836
	21st to end	Day	18% 14% 4 10% 6% 4 3 3 4 5% 28%	1570
March	1st to 10th	Day	23% 15% 5% 9% 5% 4 4 2 4 5% 25%	3116
	11th to 20th	Day	15% 20% 5% 9% 4 4 3 3 4 6% 28%	3269
	21st to end	Day	21% 10% 3 10% 5% 4 4 3 4 4 34%	4166
April	1st to 10th	Day	21% 14% 3 7% 4 4 3 3 4 5% 33%	2280
	11th to 20th	Day	18% 10% 3 7% 5% 5% 5% 4 5% 5% 34%	2254
	21st to end	Day	22% 11% 2 7% 5% 4 4 4 5% 5% 32%	2403
May	1st to 10th	Day	26% 10% 3 7% 5% 4 4 3 5% 5% 28%	4163
	11th to 20th	Day	18% 8% 3 8% 5% 4 5% 4 7% 7% 32%	4398
	21st to end	Day	14% 6% 2 6% 4 5% 5% 4 7% 7% 40%	4837
June	1st to 10th	Day	19% 7% 3 7% 5% 5% 6% 4 6% 8% 30%	2660
	11th to 20th	Day	19% 6% 2 6% 4 5% 4 5% 6% 9% 33%	2660
	21st to end	Day	18% 8% 3 7% 5% 5% 5% 4 6% 8% 29%	2660
July	1st to 10th	Day	13% 6% 2 7% 5% 4 5% 4 7% 9% 38%	4440
	11th to 20th	Day	12% 6% 3 7% 5% 5% 6% 5% 8% 9% 36%	4440
	21st to end	Day	15% 6% 2 7% 5% 5% 5% 4 7% 8% 35%	4814
August	1st to 10th	Day	18% 6% 2 7% 5% 5% 5% 4 6% 9% 32%	4397
	11th to 20th	Day	15% 6% 3 7% 5% 5% 6% 4 7% 9% 33%	3803
	21st to end	Day	14% 5% 2 5% 4 5% 5% 4 8% 8% 40%	4180
September	1st to 10th	Day	14% 6% 1 6% 4 3 4 4 6% 8% 43%	2280
	11th to 20th	Day	15% 5% 2 5% 3 3 4 4 5% 7% 47%	2173
	21st to end	Day	17% 7% 2 5% 4 3 5% 4 5% 8% 40%	2090
October	1st to 10th	Day	23% 8% 3 7% 4 5% 5% 3 4 5% 33%	2012
	11th to 20th	Day	17% 10% 4 6% 4 4 4 3 4 7% 38%	1875
	21st to end	Day	27% 10% 3 6% 4 4 5% 3 4 5% 29%	1881
November	1st to 10th	Day	15% 11% 3 6% 5% 3 3 3 5% 7% 39%	1708
	11th to 20th	Day	19% 12% 3 8% 4 4 4 3 5% 5% 33%	1710
	21st to end	Day	19% 13% 4 7% 5% 4 4 3 5% 6% 30%	1569
December	1st to 10th	Day	22% 18% 4 9% 5% 4 4 3 4 5% 23%	1520
	11th to 20th	Day	22% 16% 4 8% 5% 3 2 2 4 4 29%	1906
	21st to end	Day	25% 18% 5% 9% 4 4 3 2 4 3 23%	2772
January	1st to 10th	Night	16% 17% 6% 10% 4 4 3 3 4 4 29%	4429
	11th to 20th	Night	14% 16% 7% 14% 8% 6% 4 3 4 4 19%	4440
	21st to end	Night	23% 16% 4 12% 6% 5% 4 3 4 3 20%	4871
February	1st to 10th	Night	16% 16% 5% 11% 7% 5% 5% 4 4 4 23%	2470
	11th to 20th	Night	13% 14% 5% 12% 7% 5% 6% 3 5% 5% 25%	2228
	21st to end	Night	16% 15% 4 11% 5% 4 4 3 4 5% 29%	1884
March	1st to 10th	Night	24% 11% 3 9% 5% 5% 5% 4 4 5% 26%	3724
	11th to 20th	Night	15% 18% 4 8% 5% 4 5% 3 4 5% 29%	3684
	21st to end	Night	21% 15% 3 10% 4 3 3 2 3 4 31%	3466
April	1st to 10th	Night	22% 12% 3 7% 4 4 4 3 4 5% 31%	1900
	11th to 20th	Night	22% 11% 2 7% 4 3 3 3 5% 6% 33%	1875
	21st to end	Night	22% 11% 3 6% 4 3 4 3 4 5% 34%	1776
May	1st to 10th	Night	27% 9% 2 7% 5% 4 4 4 5% 6% 27%	2806
	11th to 20th	Night	19% 10% 4 9% 6% 4 5% 3 5% 6% 29%	2495
	21st to end	Night	16% 7% 2 6% 5% 5% 3 4 6% 8% 38%	2738
June	1st to 10th	Night	20% 7% 2 6% 4 4 4 4 6% 8% 33%	1520
	11th to 20th	Night	20% 6% 3 4 3 3 4 4 6% 8% 38%	1520
	21st to end	Night	17% 7% 2 6% 5% 4 4 4 6% 7% 38%	1520
July	1st to 10th	Night	14% 7% 3 7% 5% 5% 5% 5% 5% 7% 36%	2520
	11th to 20th	Night	19% 7% 3 6% 4 3 5% 4 5% 8% 36%	2520
	21st to end	Night	17% 6% 2 7% 4 5% 5% 3 6% 7% 37%	2739
August	1st to 10th	Night	26% 7% 3 6% 4 4 3 3 5% 7% 32%	2506
	11th to 20th	Night	16% 7% 3 7% 4 4 5% 4 7% 7% 36%	3016
	21st to end	Night	12% 6% 2 6% 4 4 5% 4 6% 8% 42%	3476
September	1st to 10th	Night	16% 7% 3 5% 3 3 4 4 5% 6% 46%	1900
	11th to 20th	Night	16% 5% 1 4 4 3 4 2 4 6% 50%	2005
	21st to end	Night	18% 6% 2 5% 4 5% 4 4 5% 5% 43%	2090
October	1st to 10th	Night	23% 7% 3 8% 4 4 3 3 5% 5% 34%	2166
	11th to 20th	Night	18% 9% 2 7% 5% 4 4 4 5% 6% 37%	2304
	21st to end	Night	26% 10% 3 6% 5% 4 4 3 5% 6% 28%	2717
November	1st to 10th	Night	16% 11% 3 7% 5% 4 4 3 4 5% 37%	2470
	11th to 20th	Night	20% 11% 3 7% 4 4 4 3 5% 6% 34%	2470
	21st to end	Night	18% 13% 4 8% 4 4 3 3 5% 6% 30%	2607
December	1st to 10th	Night	21% 18% 5% 8% 5% 4 4 4 5% 5% 21%	2660
	11th to 20th	Night	23% 15% 5% 8% 4 3 4 3 5% 4 25%	3288
	21st to end	Night	25% 17% 6% 8% 5% 4 4 3 3 4 21%	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	64% 5% 9% 19% 4	2518
	11th to 20th	Day	68% 5% 8% 14% 4 1	2520
	21st to end	Day	68% 4 10% 12% 4 1	2781
February	1st to 10th	Day	63% 5% 10% 15% 7%	1710
	11th to 20th	Day	62% 5% 8% 16% 9% 1	1845
	21st to end	Day	60% 3 10% 15% 11% 1	1570
March	1st to 10th	Day	65% 3 11% 12% 8% 1	3119
	11th to 20th	Day	59% 5% 14% 13% 8% 2	3269
	21st to end	Day	55% 4 6% 15% 17% 2	4166
April	1st to 10th	Day	56% 4 7% 20% 10% 2	2280
	11th to 20th	Day	52% 4 10% 20% 13% 1	2254
	21st to end	Day	56% 5% 9% 16% 12% 3	2403
May	1st to 10th	Day	59% 5% 10% 18% 8% 1	4177
	11th to 20th	Day	51% 5% 17% 17% 8% 1	4402
	21st to end	Day	41% 6% 13% 27% 12% 1	4837
June	1st to 10th	Day	52% 7% 14% 17% 9% 1	2660
	11th to 20th	Day	48% 6% 13% 20% 12% 1	2660
	21st to end	Day	53% 6% 12% 19% 9%	2660
July	1st to 10th	Day	42% 7% 14% 24% 12%	4370
	11th to 20th	Day	43% 7% 16% 26% 8%	4365
	21st to end	Day	46% 6% 14% 24% 9%	4661
August	1st to 10th	Day	49% 7% 15% 20% 9%	4383
	11th to 20th	Day	47% 6% 18% 24% 5% 1	3841
	21st to end	Day	39% 6% 17% 28% 10% 1	4180
September	1st to 10th	Day	40% 6% 13% 29% 11% 1	2280
	11th to 20th	Day	38% 5% 11% 28% 18% 1	2173
	21st to end	Day	43% 5% 13% 25% 12% 1	2090
October	1st to 10th	Day	52% 5% 8% 23% 12% 1	3337
	11th to 20th	Day	45% 4 13% 23% 15% 1	3091
	21st to end	Day	43% 5% 12% 28% 11% 1	3081
November	1st to 10th	Day	46% 5% 14% 22% 12% 1	1708
	11th to 20th	Day	55% 4 11% 17% 12% 1	1710
	21st to end	Day	58% 4 15% 16% 5% 1	1569
December	1st to 10th	Day	66% 4 10% 13% 5% 1	1520
	11th to 20th	Day	63% 3 12% 16% 5% 1	1906
	21st to end	Day	67% 4 8% 15% 6%	2772
January	1st to 10th	Night	62% 4 15% 13% 6%	4429
	11th to 20th	Night	68% 7% 8% 12% 5% 1	4440
	21st to end	Night	71% 4 8% 10% 6% 1	4871
February	1st to 10th	Night	66% 4 10% 14% 6% 1	2470
	11th to 20th	Night	61% 5% 10% 14% 9% 1	2230
	21st to end	Night	58% 4 11% 17% 8% 2	1884
March	1st to 10th	Night	60% 4 10% 17% 7% 1	3734
	11th to 20th	Night	57% 6% 12% 16% 7% 2	3685
	21st to end	Night	59% 4 5% 13% 17% 3	3466
April	1st to 10th	Night	57% 4 9% 18% 10% 1	1900
	11th to 20th	Night	53% 5% 8% 20% 12% 1	1875
	21st to end	Night	54% 4 9% 17% 13% 3	1776
May	1st to 10th	Night	58% 5% 10% 16% 9% 1	2812
	11th to 20th	Night	56% 6% 13% 16% 7% 1	2496
	21st to end	Night	44% 6% 14% 21% 14% 2	2739
June	1st to 10th	Night	49% 6% 14% 20% 11% 1	1520
	11th to 20th	Night	44% 6% 17% 21% 11% 1	1520
	21st to end	Night	47% 6% 13% 23% 11% 1	1520
July	1st to 10th	Night	46% 6% 15% 19% 13% 1	2480
	11th to 20th	Night	48% 6% 13% 24% 9%	2472
	21st to end	Night	46% 7% 11% 26% 9% 1	2651
August	1st to 10th	Night	52% 5% 13% 21% 8%	2496
	11th to 20th	Night	46% 7% 18% 21% 8%	3044
	21st to end	Night	38% 6% 17% 28% 11% 1	3476
September	1st to 10th	Night	40% 5% 13% 27% 14%	1900
	11th to 20th	Night	36% 4 11% 29% 19% 1	2005
	21st to end	Night	43% 5% 11% 25% 15% 2	2090
October	1st to 10th	Night	55% 5% 11% 20% 7% 1	3608
	11th to 20th	Night	44% 4 12% 22% 16% 2	3827
	21st to end	Night	48% 5% 11% 28% 7% 1	4467
November	1st to 10th	Night	51% 5% 10% 19% 12% 2	2470
	11th to 20th	Night	52% 4 11% 19% 10% 3	2470
	21st to end	Night	55% 5% 14% 18% 7%	2607
December	1st to 10th	Night	66% 5% 11% 14% 4	2660
	11th to 20th	Night	63% 5% 11% 12% 8%	3288
	21st to end	Night	69% 4 8% 16% 3	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% 21% 27% 16% 3 1	180
	11th to 20th	Day	38% 22% 29% 7% 2 1	180
	21st to end	Day	24% 25% 34% 12% 4 1	202
February	1st to 10th	Day	36% 33% 24% 7% 1	270
	11th to 20th	Day	27% 33% 27% 11% 2	444
	21st to end	Day	33% 21% 31% 14% 2	382
March	1st to 10th	Day	28% 24% 29% 16% 2	460
	11th to 20th	Day	32% 25% 26% 13% 3 1	460
	21st to end	Day	32% 25% 24% 12% 6% 2	506
April	1st to 10th	Day	38% 18% 25% 13% 5% 1	460
	11th to 20th	Day	36% 21% 23% 13% 6% 2	452
	21st to end	Day	31% 20% 28% 12% 5% 2	460
May	1st to 10th	Day	32% 20% 25% 14% 8% 2	463
	11th to 20th	Day	23% 15% 34% 21% 5% 1	487
	21st to end	Day	21% 14% 33% 21% 10% 2	529
June	1st to 10th	Day	20% 16% 33% 20% 9% 2	490
	11th to 20th	Day	22% 11% 33% 23% 9% 2	490
	21st to end	Day	23% 15% 30% 20% 9% 2	490
July	1st to 10th	Day	16% 10% 32% 26% 13% 2	485
	11th to 20th	Day	14% 7% 36% 29% 12% 2	484
	21st to end	Day	18% 6% 39% 27% 8% 2	532
August	1st to 10th	Day	16% 10% 26% 30% 14% 3	486
	11th to 20th	Day	18% 9% 28% 26% 14% 6%	479
	21st to end	Day	15% 12% 27% 27% 13% 6%	539
September	1st to 10th	Day	16% 12% 25% 24% 15% 6%	490
	11th to 20th	Day	15% 13% 25% 18% 18% 10%	490
	21st to end	Day	19% 10% 30% 22% 12% 6%	490
October	1st to 10th	Day	30% 11% 25% 17% 14% 3	490
	11th to 20th	Day	26% 17% 26% 21% 9% 1	476
	21st to end	Day	36% 15% 26% 19% 4	429
November	1st to 10th	Day	28% 19% 25% 19% 9% 1	378
	11th to 20th	Day	31% 21% 24% 18% 5% 1	370
	21st to end	Day	31% 23% 30% 13% 3	229
December	1st to 10th	Day	36% 19% 30% 11% 3 1	180
	11th to 20th	Day	33% 29% 27% 7% 3	180
	21st to end	Day	37% 23% 25% 13% 3	198
January	1st to 10th	Night	25% 24% 31% 18% 2	760
	11th to 20th	Night	29% 21% 27% 20% 2 1	760
	21st to end	Night	22% 21% 33% 20% 4	836
February	1st to 10th	Night	26% 22% 36% 15% 2	760
	11th to 20th	Night	23% 24% 34% 18% 2	743
	21st to end	Night	25% 24% 29% 19% 3	628
March	1st to 10th	Night	24% 21% 31% 20% 3	760
	11th to 20th	Night	27% 21% 31% 17% 4	760
	21st to end	Night	28% 20% 25% 19% 7%	836
April	1st to 10th	Night	30% 19% 27% 21% 4	760
	11th to 20th	Night	28% 19% 26% 19% 8%	751
	21st to end	Night	30% 16% 26% 23% 5%	636
May	1st to 10th	Night	28% 14% 26% 23% 8%	555
	11th to 20th	Night	22% 12% 31% 28% 6%	374
	21st to end	Night	18% 9% 25% 35% 12%	411
June	1st to 10th	Night	22% 8% 26% 31% 12% 1	380
	11th to 20th	Night	23% 6% 21% 38% 12%	380
	21st to end	Night	18% 7% 23% 41% 9% 1	380
July	1st to 10th	Night	18% 4 21% 43% 12% 1	370
	11th to 20th	Night	17% 4 21% 41% 16% 1	368
	21st to end	Night	16% 4 21% 46% 13% 2	416
August	1st to 10th	Night	17% 4 20% 39% 19%	378
	11th to 20th	Night	17% 5% 19% 36% 18% 4	693
	21st to end	Night	18% 5% 20% 34% 21% 2	836
September	1st to 10th	Night	19% 7% 22% 35% 16% 2	760
	11th to 20th	Night	19% 8% 19% 29% 21% 4	760
	21st to end	Night	20% 8% 26% 29% 15% 2	760
October	1st to 10th	Night	27% 11% 20% 26% 14% 1	760
	11th to 20th	Night	24% 13% 25% 29% 9%	760
	21st to end	Night	32% 13% 28% 22% 5%	836
November	1st to 10th	Night	25% 17% 29% 23% 6% 1	760
	11th to 20th	Night	26% 18% 29% 20% 6% 2	760
	21st to end	Night	26% 19% 30% 18% 5% 1	760
December	1st to 10th	Night	33% 21% 26% 16% 4	760
	11th to 20th	Night	29% 22% 27% 18% 4	760
	21st to end	Night	31% 20% 31% 16% 2	836

Page generated at 2024-11-03 02:11:20. Version ac07

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