Quispamsis
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Quispamsis clear sky chart from 2005-11-06 to 2025-06-10.

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	20% 10% 3 7% 5% 4 4 3 5% 6% 32%	119377
	Night	21% 11% 3 7% 4 4 4 3 5% 5% 32%	118950
Transparency	Day	53% 4 11% 20% 11% 1	122937
	Night	53% 4 10% 20% 11% 1	123551
Seeing	Day	30% 19% 30% 16% 5% 1	17280
	Night	28% 16% 28% 21% 6%	25157

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% 16% 5% 11% 6% 5% 4 3 3 4 28%	3157
	11th to 20th	Day	13% 15% 5% 10% 6% 4 3 3 3 4 34%	3479
	21st to end	Day	11% 9% 3 7% 5% 5% 5% 4 5% 6% 39%	4466
February	1st to 10th	Day	17% 13% 4 7% 5% 5% 5% 4 5% 6% 31%	1800
	11th to 20th	Day	15% 13% 3 9% 6% 5% 4 3 5% 6% 31%	1753
	21st to end	Day	11% 12% 4 8% 6% 4 4 4 5% 6% 36%	1580
March	1st to 10th	Day	23% 13% 3 13% 4 3 3 2 4 4 27%	4787
	11th to 20th	Day	19% 16% 4 8% 4 4 4 3 5% 6% 28%	4980
	21st to end	Day	28% 12% 4 8% 4 4 4 3 5% 5% 23%	5466
April	1st to 10th	Day	22% 14% 3 8% 5% 4 3 3 4 5% 28%	2320
	11th to 20th	Day	20% 11% 2 6% 5% 4 3 3 5% 6% 34%	2572
	21st to end	Day	23% 9% 3 7% 4 4 3 3 5% 6% 32%	2600
May	1st to 10th	Day	27% 12% 3 7% 5% 5% 5% 3 5% 5% 22%	5886
	11th to 20th	Day	23% 9% 3 7% 4 4 4 3 5% 6% 31%	6226
	21st to end	Day	21% 9% 3 6% 5% 5% 5% 4 6% 8% 29%	6984
June	1st to 10th	Day	24% 10% 3 7% 5% 5% 5% 3 5% 7% 28%	2985
	11th to 20th	Day	21% 9% 3 7% 5% 4 3 3 5% 6% 34%	2850
	21st to end	Day	29% 8% 2 7% 4 4 3 3 5% 6% 28%	2850
July	1st to 10th	Day	19% 8% 3 8% 5% 5% 5% 4 6% 7% 31%	4760
	11th to 20th	Day	24% 9% 2 6% 4 3 4 4 5% 7% 34%	4760
	21st to end	Day	20% 7% 3 7% 5% 4 4 4 6% 7% 34%	4492
August	1st to 10th	Day	24% 9% 3 7% 4 4 4 3 5% 7% 29%	4105
	11th to 20th	Day	18% 7% 2 6% 4 4 5% 4 6% 8% 35%	4045
	21st to end	Day	13% 6% 2 5% 4 3 4 3 5% 8% 45%	4506
September	1st to 10th	Day	15% 7% 2 6% 4 4 4 3 5% 7% 43%	2277
	11th to 20th	Day	18% 6% 2 5% 3 3 4 3 4 6% 46%	2090
	21st to end	Day	22% 5% 2 4 3 3 3 3 5% 6% 44%	2090
October	1st to 10th	Day	17% 8% 2 7% 5% 4 4 3 5% 6% 39%	1914
	11th to 20th	Day	21% 8% 2 6% 4 4 4 3 4 5% 38%	1900
	21st to end	Day	20% 10% 4 7% 5% 4 4 3 5% 6% 33%	2008
November	1st to 10th	Day	23% 9% 2 6% 5% 4 3 2 4 6% 35%	1676
	11th to 20th	Day	20% 9% 3 6% 4 3 5% 3 4 7% 36%	1600
	21st to end	Day	21% 13% 4 7% 4 4 5% 4 4 5% 30%	1600
December	1st to 10th	Day	21% 10% 3 8% 5% 3 3 3 4 6% 32%	2610
	11th to 20th	Day	25% 12% 3 7% 4 3 2 2 3 4 35%	2727
	21st to end	Day	20% 11% 3 6% 3 4 4 4 4 7% 34%	3476
January	1st to 10th	Night	14% 13% 4 9% 6% 5% 5% 4 5% 5% 31%	6808
	11th to 20th	Night	17% 11% 5% 9% 5% 4 4 3 5% 5% 32%	6392
	21st to end	Night	12% 12% 3 7% 5% 4 3 3 5% 7% 39%	6490
February	1st to 10th	Night	18% 12% 3 7% 5% 4 4 5% 5% 6% 31%	2600
	11th to 20th	Night	16% 13% 4 8% 5% 5% 5% 4 5% 5% 30%	2533
	21st to end	Night	14% 12% 4 8% 6% 4 5% 4 5% 5% 34%	2046
March	1st to 10th	Night	26% 13% 4 8% 4 5% 4 3 3 4 26%	5051
	11th to 20th	Night	21% 15% 4 8% 4 5% 4 3 5% 5% 26%	4979
	21st to end	Night	31% 11% 3 6% 4 4 4 3 3 4 28%	5466
April	1st to 10th	Night	23% 12% 3 7% 5% 4 4 3 4 3 30%	2076
	11th to 20th	Night	24% 10% 2 6% 4 4 4 3 4 5% 33%	1778
	21st to end	Night	24% 9% 3 7% 4 3 4 4 6% 6% 29%	1800
May	1st to 10th	Night	26% 12% 3 9% 5% 4 5% 4 4 5% 24%	4054
	11th to 20th	Night	23% 11% 2 6% 4 3 4 4 5% 5% 32%	3684
	21st to end	Night	20% 13% 3 8% 4 4 4 3 5% 6% 30%	3948
June	1st to 10th	Night	26% 11% 2 7% 4 5% 4 3 5% 7% 25%	1404
	11th to 20th	Night	22% 10% 3 7% 5% 4 3 3 5% 5% 32%	1330
	21st to end	Night	31% 9% 4 6% 5% 4 5% 2 4 5% 26%	1330
July	1st to 10th	Night	23% 13% 4 9% 5% 4 4 5% 4 5% 24%	2210
	11th to 20th	Night	26% 15% 3 6% 3 4 4 3 5% 6% 25%	2210
	21st to end	Night	21% 9% 2 7% 3 4 5% 4 5% 7% 31%	3011
August	1st to 10th	Night	26% 12% 3 8% 5% 4 4 2 5% 6% 25%	2825
	11th to 20th	Night	18% 11% 2 8% 5% 5% 5% 4 5% 7% 31%	2782
	21st to end	Night	14% 8% 3 5% 4 4 4 3 5% 7% 43%	3149
September	1st to 10th	Night	18% 7% 2 6% 4 4 4 3 6% 7% 40%	1900
	11th to 20th	Night	20% 6% 2 6% 3 3 3 2 5% 6% 43%	2090
	21st to end	Night	22% 6% 2 5% 4 4 3 3 4 7% 41%	2090
October	1st to 10th	Night	21% 6% 3 5% 4 4 3 3 5% 7% 39%	2265
	11th to 20th	Night	18% 9% 3 7% 4 4 4 3 5% 5% 38%	2280
	21st to end	Night	22% 11% 3 7% 4 4 3 4 4 5% 34%	2589
November	1st to 10th	Night	22% 9% 2 6% 4 4 4 3 5% 6% 36%	2621
	11th to 20th	Night	21% 10% 3 7% 4 4 4 4 5% 6% 33%	2800
	21st to end	Night	22% 11% 3 7% 4 4 4 3 5% 5% 32%	2800
December	1st to 10th	Night	18% 11% 4 8% 4 4 3 3 4 5% 35%	4580
	11th to 20th	Night	24% 11% 2 6% 4 3 3 3 4 4 37%	5477
	21st to end	Night	20% 14% 4 8% 4 3 3 3 5% 5% 32%	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	59% 5% 12% 16% 7%	3158
	11th to 20th	Day	55% 5% 8% 22% 9% 1	3509
	21st to end	Day	46% 3 10% 17% 20% 4	4466
February	1st to 10th	Day	55% 4 10% 19% 11% 2	1800
	11th to 20th	Day	54% 3 11% 18% 12% 2	1761
	21st to end	Day	49% 5% 9% 23% 11% 3	1580
March	1st to 10th	Day	62% 3 7% 14% 12% 3	4791
	11th to 20th	Day	56% 5% 12% 17% 8% 1	4980
	21st to end	Day	63% 4 4 15% 11% 2	5466
April	1st to 10th	Day	59% 3 7% 15% 13% 3	2320
	11th to 20th	Day	51% 4 8% 22% 13% 1	2572
	21st to end	Day	53% 4 10% 18% 12% 3	2600
May	1st to 10th	Day	66% 4 6% 17% 6% 1	5897
	11th to 20th	Day	53% 4 12% 21% 7% 2	6230
	21st to end	Day	55% 4 11% 19% 11%	6984
June	1st to 10th	Day	57% 5% 9% 20% 9% 1	2985
	11th to 20th	Day	51% 4 10% 22% 11% 2	2850
	21st to end	Day	58% 5% 11% 16% 10% 1	2850
July	1st to 10th	Day	52% 6% 13% 19% 10%	4685
	11th to 20th	Day	52% 4 13% 23% 8%	4679
	21st to end	Day	50% 6% 13% 24% 7%	4348
August	1st to 10th	Day	56% 5% 11% 21% 7%	4092
	11th to 20th	Day	46% 6% 15% 25% 8%	4084
	21st to end	Day	37% 5% 15% 26% 17% 1	4506
September	1st to 10th	Day	41% 4 12% 27% 15% 1	2277
	11th to 20th	Day	41% 4 10% 27% 15% 2	2090
	21st to end	Day	43% 4 9% 27% 16% 1	2090
October	1st to 10th	Day	46% 6% 10% 28% 10%	3174
	11th to 20th	Day	46% 4 9% 31% 10%	3140
	21st to end	Day	41% 5% 16% 21% 17%	3284
November	1st to 10th	Day	53% 4 10% 22% 11% 1	1676
	11th to 20th	Day	49% 5% 12% 18% 14% 2	1600
	21st to end	Day	57% 4 11% 21% 7%	1600
December	1st to 10th	Day	54% 4 14% 21% 6%	2610
	11th to 20th	Day	56% 3 9% 17% 13% 3	2727
	21st to end	Day	51% 4 11% 20% 13% 2	3476
January	1st to 10th	Night	53% 5% 11% 25% 5% 1	6808
	11th to 20th	Night	53% 5% 10% 23% 8% 1	6437
	21st to end	Night	45% 3 7% 24% 17% 4	6490
February	1st to 10th	Night	53% 4 11% 17% 14% 2	2600
	11th to 20th	Night	55% 4 9% 19% 11% 2	2536
	21st to end	Night	52% 4 8% 21% 12% 3	2046
March	1st to 10th	Night	62% 3 5% 13% 12% 4	5060
	11th to 20th	Night	60% 4 12% 15% 8% 1	4980
	21st to end	Night	62% 3 4 17% 11% 1	5466
April	1st to 10th	Night	58% 3 7% 15% 12% 4	2076
	11th to 20th	Night	53% 3 9% 21% 13% 1	1778
	21st to end	Night	55% 4 8% 18% 13% 2	1800
May	1st to 10th	Night	64% 4 9% 14% 8% 1	4060
	11th to 20th	Night	55% 3 12% 22% 6% 2	3685
	21st to end	Night	56% 4 12% 19% 8% 1	3949
June	1st to 10th	Night	59% 4 9% 19% 7% 1	1404
	11th to 20th	Night	53% 5% 11% 22% 8% 2	1330
	21st to end	Night	62% 4 7% 17% 8% 1	1330
July	1st to 10th	Night	63% 5% 10% 11% 11%	2175
	11th to 20th	Night	62% 5% 8% 18% 7%	2168
	21st to end	Night	51% 6% 13% 19% 10% 1	2915
August	1st to 10th	Night	62% 5% 9% 18% 6%	2813
	11th to 20th	Night	52% 6% 15% 21% 7%	2809
	21st to end	Night	41% 6% 11% 24% 17% 1	3148
September	1st to 10th	Night	44% 3 11% 27% 14% 1	1900
	11th to 20th	Night	44% 3 11% 25% 16% 1	2090
	21st to end	Night	45% 4 8% 27% 14% 2	2090
October	1st to 10th	Night	46% 5% 12% 24% 12% 1	3785
	11th to 20th	Night	41% 4 10% 28% 17%	3779
	21st to end	Night	46% 4 12% 23% 15% 1	4263
November	1st to 10th	Night	50% 4 12% 21% 12% 1	2621
	11th to 20th	Night	53% 4 9% 20% 13% 1	2800
	21st to end	Night	53% 5% 13% 18% 10% 1	2800
December	1st to 10th	Night	50% 5% 11% 25% 9%	4580
	11th to 20th	Night	54% 4 6% 21% 14% 2	5478
	21st to end	Night	55% 4 9% 18% 11% 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	32% 26% 31% 11% 1	200
	11th to 20th	Day	37% 21% 29% 10% 2	201
	21st to end	Day	21% 26% 36% 14% 3	440
February	1st to 10th	Day	32% 26% 26% 13% 3	400
	11th to 20th	Day	29% 30% 28% 11% 2 1	396
	21st to end	Day	26% 29% 30% 14% 2	379
March	1st to 10th	Day	31% 25% 32% 10% 2	500
	11th to 20th	Day	29% 24% 31% 12% 3 1	500
	21st to end	Day	38% 22% 27% 9% 4 1	550
April	1st to 10th	Day	39% 30% 21% 8% 2	500
	11th to 20th	Day	36% 24% 25% 10% 4	492
	21st to end	Day	33% 22% 28% 11% 4 1	500
May	1st to 10th	Day	36% 19% 31% 11% 3	503
	11th to 20th	Day	29% 18% 29% 19% 4 1	684
	21st to end	Day	32% 18% 29% 17% 4 1	790
June	1st to 10th	Day	33% 17% 27% 17% 5%	725
	11th to 20th	Day	28% 15% 29% 21% 6% 1	680
	21st to end	Day	35% 12% 27% 19% 7% 1	680
July	1st to 10th	Day	30% 10% 32% 21% 7% 1	670
	11th to 20th	Day	29% 8% 31% 23% 8% 2	668
	21st to end	Day	27% 13% 36% 18% 6% 1	547
August	1st to 10th	Day	24% 11% 33% 26% 6% 1	486
	11th to 20th	Day	27% 9% 35% 21% 7% 1	479
	21st to end	Day	23% 13% 29% 25% 8% 2	539
September	1st to 10th	Day	18% 14% 40% 20% 6% 2	490
	11th to 20th	Day	27% 13% 29% 20% 8% 3	490
	21st to end	Day	24% 16% 33% 19% 6% 2	490
October	1st to 10th	Day	24% 16% 27% 21% 11% 2	397
	11th to 20th	Day	25% 18% 30% 18% 7% 2	390
	21st to end	Day	27% 21% 33% 15% 3 1	429
November	1st to 10th	Day	31% 18% 31% 13% 5% 2	395
	11th to 20th	Day	32% 23% 26% 15% 4	400
	21st to end	Day	36% 24% 28% 9% 3 1	400
December	1st to 10th	Day	35% 20% 28% 14% 3	400
	11th to 20th	Day	37% 29% 24% 9% 2	270
	21st to end	Day	33% 27% 26% 11% 2	220
January	1st to 10th	Night	28% 24% 28% 17% 4	900
	11th to 20th	Night	30% 20% 27% 18% 4	820
	21st to end	Night	21% 26% 33% 16% 4	880
February	1st to 10th	Night	29% 23% 28% 18% 2	800
	11th to 20th	Night	27% 26% 28% 16% 2	783
	21st to end	Night	24% 21% 29% 22% 3 1	660
March	1st to 10th	Night	27% 21% 34% 17% 2	800
	11th to 20th	Night	26% 18% 31% 21% 4	800
	21st to end	Night	28% 19% 30% 17% 5% 1	880
April	1st to 10th	Night	32% 19% 30% 17% 3	689
	11th to 20th	Night	31% 15% 33% 17% 5%	594
	21st to end	Night	30% 16% 29% 20% 5%	600
May	1st to 10th	Night	31% 12% 30% 22% 5% 1	600
	11th to 20th	Night	31% 11% 32% 21% 5%	592
	21st to end	Night	29% 14% 35% 19% 4	649
June	1st to 10th	Night	36% 6% 26% 27% 5%	405
	11th to 20th	Night	28% 8% 28% 31% 5%	380
	21st to end	Night	36% 5% 23% 29% 7% 1	380
July	1st to 10th	Night	29% 6% 26% 31% 8%	370
	11th to 20th	Night	32% 5% 23% 31% 9% 1	368
	21st to end	Night	28% 5% 28% 30% 8%	591
August	1st to 10th	Night	23% 5% 29% 33% 10% 1	568
	11th to 20th	Night	29% 7% 24% 30% 10%	562
	21st to end	Night	23% 7% 26% 30% 14% 1	627
September	1st to 10th	Night	23% 7% 32% 28% 9% 1	570
	11th to 20th	Night	25% 9% 23% 27% 14% 1	760
	21st to end	Night	26% 10% 27% 24% 11% 1	760
October	1st to 10th	Night	26% 8% 25% 28% 11% 2	760
	11th to 20th	Night	24% 16% 29% 21% 10% 1	760
	21st to end	Night	30% 18% 27% 22% 3	836
November	1st to 10th	Night	29% 17% 28% 18% 8% 1	823
	11th to 20th	Night	29% 21% 25% 19% 6% 1	900
	21st to end	Night	32% 21% 23% 19% 4	900
December	1st to 10th	Night	33% 20% 27% 17% 3	900
	11th to 20th	Night	32% 26% 27% 13% 2	900
	21st to end	Night	31% 23% 24% 17% 4	990

Page generated at 2025-06-07 11:28:16. Version ac07

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