Tignish
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tignish clear sky chart from 2005-11-06 to 2024-11-04.

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	17% 10% 4 8% 5% 4 4 3 5% 7% 32%	101741
	Night	18% 12% 4 10% 6% 5% 4 3 5% 6% 28%	97348
Transparency	Day	52% 5% 13% 20% 9% 1	105280
	Night	58% 5% 12% 17% 8% 1	101888
Seeing	Day	22% 9% 26% 28% 13% 3	16906
	Night	25% 10% 28% 26% 10% 1	24327

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	15% 13% 7% 19% 9% 5% 5% 4 5% 5% 13%	2207
	11th to 20th	Day	12% 13% 5% 13% 9% 6% 5% 4 4 4 24%	2314
	21st to end	Day	9% 10% 5% 12% 9% 5% 5% 4 5% 7% 31%	3067
February	1st to 10th	Day	16% 13% 3 8% 5% 6% 4 4 5% 5% 32%	1710
	11th to 20th	Day	14% 14% 4 8% 6% 5% 4 4 4 6% 30%	1663
	21st to end	Day	11% 12% 4 7% 6% 5% 4 4 5% 6% 36%	1413
March	1st to 10th	Day	18% 13% 5% 8% 5% 5% 4 3 4 6% 30%	3384
	11th to 20th	Day	15% 15% 5% 13% 6% 6% 5% 3 4 5% 22%	3480
	21st to end	Day	25% 14% 4 7% 4 4 4 3 4 6% 25%	3832
April	1st to 10th	Day	19% 11% 4 8% 4 4 4 3 5% 6% 32%	2280
	11th to 20th	Day	18% 9% 3 5% 4 3 4 3 5% 8% 37%	2371
	21st to end	Day	20% 11% 4 7% 4 4 4 4 5% 6% 32%	2470
May	1st to 10th	Day	23% 11% 3 6% 4 3 4 4 4 7% 31%	4323
	11th to 20th	Day	15% 8% 2 6% 5% 4 4 3 5% 6% 41%	4398
	21st to end	Day	16% 8% 3 8% 5% 5% 5% 4 6% 8% 32%	4836
June	1st to 10th	Day	24% 10% 3 7% 5% 4 4 3 6% 6% 28%	2819
	11th to 20th	Day	17% 9% 3 7% 5% 4 4 4 5% 6% 36%	2850
	21st to end	Day	23% 9% 3 7% 5% 4 4 4 5% 7% 31%	2850
July	1st to 10th	Day	12% 7% 3 8% 5% 6% 5% 5% 6% 8% 36%	4760
	11th to 20th	Day	13% 7% 2 7% 4 4 5% 4 7% 8% 39%	4696
	21st to end	Day	12% 7% 3 6% 4 4 4 3 6% 8% 44%	4815
August	1st to 10th	Day	14% 8% 3 7% 5% 5% 5% 5% 6% 7% 35%	4121
	11th to 20th	Day	13% 6% 2 6% 5% 5% 5% 4 6% 8% 40%	4045
	21st to end	Day	15% 5% 1 5% 4 4 4 3 5% 7% 47%	4410
September	1st to 10th	Day	16% 6% 3 4 3 4 4 4 6% 8% 43%	2280
	11th to 20th	Day	19% 7% 2 5% 3 4 4 3 4 6% 44%	2215
	21st to end	Day	18% 7% 2 5% 4 4 4 3 5% 7% 42%	2025
October	1st to 10th	Day	19% 8% 2 7% 4 3 4 4 4 7% 38%	1900
	11th to 20th	Day	19% 12% 4 7% 5% 4 4 3 4 8% 29%	1900
	21st to end	Day	21% 15% 3 8% 5% 4 4 3 5% 7% 25%	2030
November	1st to 10th	Day	19% 17% 5% 7% 5% 4 4 3 5% 6% 25%	1509
	11th to 20th	Day	18% 19% 5% 11% 7% 5% 3 3 5% 7% 17%	1520
	21st to end	Day	18% 18% 8% 15% 6% 4 3 3 5% 5% 15%	1520
December	1st to 10th	Day	24% 16% 8% 15% 7% 4 3 3 4 3 13%	1520
	11th to 20th	Day	17% 19% 7% 18% 9% 6% 3 2 4 2 14%	1777
	21st to end	Day	18% 13% 10% 18% 7% 5% 3 2 3 4 17%	2431
January	1st to 10th	Night	12% 14% 7% 20% 8% 5% 4 3 4 6% 16%	4748
	11th to 20th	Night	17% 14% 5% 13% 8% 5% 4 3 4 5% 22%	4652
	21st to end	Night	10% 13% 4 12% 11% 5% 5% 4 5% 7% 24%	4587
February	1st to 10th	Night	15% 13% 4 8% 6% 5% 5% 4 5% 6% 30%	2470
	11th to 20th	Night	15% 14% 5% 9% 5% 5% 5% 4 4 5% 28%	2403
	21st to end	Night	12% 14% 3 8% 6% 4 5% 3 5% 6% 33%	2041
March	1st to 10th	Night	19% 12% 4 10% 6% 5% 4 3 4 5% 28%	3453
	11th to 20th	Night	23% 17% 5% 10% 6% 5% 4 3 4 4 20%	3479
	21st to end	Night	27% 12% 4 9% 5% 4 3 3 4 5% 24%	3799
April	1st to 10th	Night	22% 12% 3 8% 5% 4 4 3 4 6% 28%	1900
	11th to 20th	Night	21% 11% 3 7% 3 4 3 3 5% 6% 34%	1756
	21st to end	Night	21% 12% 4 7% 4 4 4 2 4 5% 32%	1710
May	1st to 10th	Night	27% 11% 3 7% 5% 5% 3 4 4 6% 25%	2623
	11th to 20th	Night	14% 8% 3 7% 5% 4 4 4 5% 8% 40%	2506
	21st to end	Night	16% 9% 4 9% 6% 6% 5% 5% 6% 7% 27%	2749
June	1st to 10th	Night	24% 12% 3 6% 5% 4 4 4 5% 6% 27%	1377
	11th to 20th	Night	18% 7% 3 6% 6% 5% 4 4 6% 7% 35%	1330
	21st to end	Night	21% 10% 3 8% 5% 5% 4 4 5% 7% 27%	1330
July	1st to 10th	Night	12% 9% 3 9% 7% 5% 5% 4 6% 7% 35%	2210
	11th to 20th	Night	14% 8% 3 7% 7% 6% 5% 4 6% 8% 32%	2241
	21st to end	Night	12% 6% 3 6% 4 4 4 5% 6% 8% 42%	2750
August	1st to 10th	Night	16% 8% 3 9% 6% 6% 7% 5% 6% 6% 29%	2794
	11th to 20th	Night	10% 7% 3 8% 5% 6% 4 4 7% 8% 38%	2782
	21st to end	Night	13% 5% 2 6% 5% 5% 4 4 5% 7% 44%	3245
September	1st to 10th	Night	16% 7% 3 6% 4 4 3 3 4 8% 43%	1900
	11th to 20th	Night	17% 7% 2 6% 3 3 4 3 4 7% 44%	1962
	21st to end	Night	17% 7% 2 7% 3 4 4 3 5% 6% 43%	2154
October	1st to 10th	Night	20% 7% 2 6% 4 4 4 4 6% 5% 37%	2280
	11th to 20th	Night	19% 12% 3 9% 5% 4 4 3 4 7% 31%	2280
	21st to end	Night	25% 13% 4 9% 5% 4 4 3 4 6% 25%	2562
November	1st to 10th	Night	22% 15% 4 8% 5% 3 4 3 4 6% 27%	2642
	11th to 20th	Night	20% 17% 5% 12% 5% 4 4 3 5% 6% 19%	2660
	21st to end	Night	22% 18% 6% 14% 5% 4 3 2 6% 4 16%	2660
December	1st to 10th	Night	25% 18% 8% 14% 5% 4 3 3 4 4 13%	2660
	11th to 20th	Night	19% 20% 8% 19% 7% 4 2 2 3 4 13%	3417
	21st to end	Night	23% 14% 6% 15% 6% 5% 3 2 3 5% 18%	5236

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	74% 7% 8% 7% 3	2208
	11th to 20th	Day	65% 5% 8% 14% 7% 1	2314
	21st to end	Day	54% 5% 15% 14% 10% 1	3067
February	1st to 10th	Day	54% 5% 12% 19% 9% 1	1710
	11th to 20th	Day	56% 5% 10% 20% 8% 1	1671
	21st to end	Day	49% 4 11% 20% 13% 2	1413
March	1st to 10th	Day	57% 4 11% 22% 6% 1	3388
	11th to 20th	Day	62% 7% 9% 15% 6% 1	3480
	21st to end	Day	61% 4 8% 16% 10% 2	3832
April	1st to 10th	Day	52% 6% 10% 17% 13% 2	2280
	11th to 20th	Day	46% 5% 11% 22% 14% 1	2371
	21st to end	Day	51% 6% 10% 17% 13% 3	2470
May	1st to 10th	Day	52% 6% 12% 20% 10% 1	4338
	11th to 20th	Day	44% 6% 14% 28% 8%	4402
	21st to end	Day	48% 8% 12% 21% 10%	4836
June	1st to 10th	Day	57% 6% 11% 20% 6%	2819
	11th to 20th	Day	47% 6% 13% 23% 10% 1	2850
	21st to end	Day	52% 8% 13% 18% 8% 1	2850
July	1st to 10th	Day	45% 5% 20% 19% 10%	4685
	11th to 20th	Day	43% 5% 18% 26% 8%	4615
	21st to end	Day	39% 7% 22% 24% 8%	4662
August	1st to 10th	Day	48% 6% 15% 24% 7%	4107
	11th to 20th	Day	42% 6% 15% 25% 12%	4084
	21st to end	Day	37% 5% 16% 29% 12% 1	4410
September	1st to 10th	Day	38% 7% 16% 27% 12%	2280
	11th to 20th	Day	43% 5% 15% 25% 12% 1	2215
	21st to end	Day	42% 6% 12% 27% 12%	2025
October	1st to 10th	Day	48% 3 14% 27% 8%	3160
	11th to 20th	Day	55% 3 11% 24% 6%	3140
	21st to end	Day	53% 4 18% 17% 7%	3322
November	1st to 10th	Day	60% 5% 11% 17% 6% 1	1509
	11th to 20th	Day	70% 5% 13% 8% 5%	1520
	21st to end	Day	72% 7% 13% 6% 2	1520
December	1st to 10th	Day	78% 4 7% 8% 3	1520
	11th to 20th	Day	80% 3 5% 7% 4	1776
	21st to end	Day	74% 4 10% 7% 4	2431
January	1st to 10th	Night	70% 5% 13% 9% 2	4748
	11th to 20th	Night	65% 6% 8% 14% 7%	4652
	21st to end	Night	61% 6% 12% 15% 5% 1	4587
February	1st to 10th	Night	55% 5% 11% 16% 11% 2	2470
	11th to 20th	Night	57% 5% 9% 17% 11% 1	2406
	21st to end	Night	52% 4 9% 20% 13% 2	2041
March	1st to 10th	Night	60% 4 8% 18% 8% 2	3462
	11th to 20th	Night	66% 7% 7% 13% 5% 1	3480
	21st to end	Night	64% 3 6% 16% 10% 1	3799
April	1st to 10th	Night	57% 4 10% 14% 13% 1	1900
	11th to 20th	Night	51% 4 8% 23% 11% 2	1756
	21st to end	Night	55% 5% 8% 15% 14% 3	1710
May	1st to 10th	Night	60% 5% 8% 18% 8% 1	2628
	11th to 20th	Night	42% 7% 14% 27% 9% 1	2507
	21st to end	Night	52% 9% 14% 17% 7%	2750
June	1st to 10th	Night	56% 6% 12% 18% 7%	1377
	11th to 20th	Night	47% 6% 12% 24% 10% 1	1330
	21st to end	Night	56% 6% 13% 17% 8%	1330
July	1st to 10th	Night	49% 4 16% 20% 10%	2175
	11th to 20th	Night	49% 5% 16% 24% 6%	2199
	21st to end	Night	39% 7% 24% 20% 10%	2663
August	1st to 10th	Night	54% 7% 14% 20% 6%	2783
	11th to 20th	Night	43% 5% 18% 23% 10% 1	2809
	21st to end	Night	40% 5% 16% 26% 13% 1	3244
September	1st to 10th	Night	41% 6% 12% 29% 11%	1900
	11th to 20th	Night	42% 5% 13% 29% 11%	1962
	21st to end	Night	42% 6% 12% 28% 12% 1	2154
October	1st to 10th	Night	53% 3 13% 24% 7%	3800
	11th to 20th	Night	53% 3 10% 26% 8%	3779
	21st to end	Night	57% 4 12% 18% 8%	4210
November	1st to 10th	Night	61% 5% 12% 15% 6% 1	2642
	11th to 20th	Night	68% 6% 10% 12% 4	2660
	21st to end	Night	71% 6% 11% 8% 3	2660
December	1st to 10th	Night	77% 4 8% 8% 3	2660
	11th to 20th	Night	79% 3 6% 8% 2	3419
	21st to end	Night	72% 4 12% 9% 3	5236

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% 18% 29% 23% 3	180
	11th to 20th	Day	27% 18% 30% 19% 4 2	245
	21st to end	Day	16% 10% 40% 26% 8%	407
February	1st to 10th	Day	26% 14% 32% 22% 5% 2	370
	11th to 20th	Day	20% 17% 38% 20% 5% 1	366
	21st to end	Day	18% 10% 35% 28% 7% 1	307
March	1st to 10th	Day	20% 11% 36% 23% 8% 1	445
	11th to 20th	Day	15% 11% 35% 24% 13% 2	460
	21st to end	Day	26% 13% 28% 22% 9% 2	506
April	1st to 10th	Day	26% 11% 33% 21% 8% 1	460
	11th to 20th	Day	21% 10% 31% 27% 8% 2	452
	21st to end	Day	23% 10% 24% 27% 13% 2	460
May	1st to 10th	Day	29% 6% 28% 23% 11% 3	590
	11th to 20th	Day	21% 5% 24% 29% 16% 5%	674
	21st to end	Day	22% 6% 28% 31% 12% 1	735
June	1st to 10th	Day	28% 5% 24% 30% 10% 3	680
	11th to 20th	Day	21% 4 21% 34% 17% 3	680
	21st to end	Day	26% 4 18% 33% 16% 3	680
July	1st to 10th	Day	17% 2 24% 32% 22% 3	670
	11th to 20th	Day	14% 4 17% 37% 23% 4	668
	21st to end	Day	17% 3 16% 38% 21% 4	740
August	1st to 10th	Day	13% 3 18% 36% 24% 6%	502
	11th to 20th	Day	16% 6% 14% 32% 26% 6%	479
	21st to end	Day	18% 5% 19% 31% 22% 6%	539
September	1st to 10th	Day	15% 4 26% 37% 15% 3	490
	11th to 20th	Day	22% 8% 22% 27% 17% 4	490
	21st to end	Day	21% 7% 27% 26% 17% 2	455
October	1st to 10th	Day	22% 10% 19% 30% 16% 3	390
	11th to 20th	Day	25% 11% 28% 24% 11% 1	390
	21st to end	Day	28% 13% 31% 21% 6% 1	429
November	1st to 10th	Day	25% 14% 34% 22% 4 1	374
	11th to 20th	Day	31% 15% 29% 19% 5% 1	370
	21st to end	Day	31% 16% 31% 20% 2	370
December	1st to 10th	Day	31% 12% 38% 15% 3 1	370
	11th to 20th	Day	28% 24% 30% 15% 3	285
	21st to end	Day	19% 25% 36% 17% 3	198
January	1st to 10th	Night	26% 15% 34% 20% 5%	850
	11th to 20th	Night	26% 14% 33% 20% 7%	850
	21st to end	Night	19% 14% 36% 22% 8% 1	850
February	1st to 10th	Night	23% 12% 34% 22% 8% 1	760
	11th to 20th	Night	23% 13% 37% 21% 4 1	743
	21st to end	Night	18% 11% 31% 29% 10% 1	628
March	1st to 10th	Night	23% 9% 34% 28% 5%	760
	11th to 20th	Night	21% 10% 31% 26% 10% 2	760
	21st to end	Night	25% 11% 29% 23% 10% 1	831
April	1st to 10th	Night	28% 9% 28% 26% 9%	570
	11th to 20th	Night	24% 7% 30% 26% 11% 2	564
	21st to end	Night	25% 8% 27% 27% 11% 1	570
May	1st to 10th	Night	29% 4 25% 27% 11% 4	570
	11th to 20th	Night	21% 3 23% 31% 17% 4	562
	21st to end	Night	18% 5% 31% 35% 9% 1	616
June	1st to 10th	Night	31% 4 20% 34% 11% 1	427
	11th to 20th	Night	20% 3 20% 35% 21% 2	380
	21st to end	Night	24% 3 16% 40% 14% 3	380
July	1st to 10th	Night	18% 3 21% 39% 16% 3	370
	11th to 20th	Night	14% 3 22% 40% 20% 1	386
	21st to end	Night	18% 3 18% 41% 18% 2	623
August	1st to 10th	Night	18% 2 19% 41% 19% 1	568
	11th to 20th	Night	20% 3 17% 36% 23% 2	562
	21st to end	Night	15% 4 18% 38% 22% 4	627
September	1st to 10th	Night	20% 6% 27% 34% 12% 2	570
	11th to 20th	Night	21% 8% 21% 33% 16% 1	632
	21st to end	Night	21% 7% 27% 32% 13% 1	760
October	1st to 10th	Night	25% 7% 27% 28% 12% 1	760
	11th to 20th	Night	25% 11% 28% 24% 11% 1	760
	21st to end	Night	34% 14% 28% 19% 5%	855
November	1st to 10th	Night	32% 15% 27% 21% 5% 1	848
	11th to 20th	Night	28% 17% 29% 18% 6% 2	850
	21st to end	Night	33% 16% 27% 20% 4	850
December	1st to 10th	Night	34% 13% 33% 17% 3	850
	11th to 20th	Night	30% 22% 30% 14% 4	850
	21st to end	Night	31% 17% 27% 20% 4 1	935

Page generated at 2024-11-01 23:47:49. Version ac07

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