Parry Sound
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Parry Sound clear sky chart from 2005-11-06 to 2025-04-11.

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 8% 5% 4 4 3 5% 6% 32%	113517
	Night	16% 13% 5% 10% 5% 4 4 3 5% 6% 29%	114792
Transparency	Day	52% 5% 11% 21% 10% 1	117118
	Night	56% 4 10% 19% 10% 1	119356
Seeing	Day	23% 13% 31% 21% 9% 2	15512
	Night	24% 10% 29% 26% 10% 1	24760

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% 19% 10% 10% 4 3 4 3 4 6% 26%	3158
	11th to 20th	Day	9% 20% 8% 20% 7% 7% 5% 3 4 4 13%	3634
	21st to end	Day	14% 19% 8% 16% 6% 6% 5% 3 3 4 17%	4466
February	1st to 10th	Day	13% 20% 6% 13% 7% 4 3 4 4 4 21%	1800
	11th to 20th	Day	12% 17% 6% 11% 6% 6% 3 2 5% 5% 26%	1753
	21st to end	Day	15% 17% 6% 13% 6% 4 4 3 5% 4 22%	1530
March	1st to 10th	Day	19% 14% 5% 10% 5% 5% 3 3 3 4 29%	4882
	11th to 20th	Day	13% 14% 5% 9% 6% 5% 4 4 5% 7% 27%	4980
	21st to end	Day	18% 15% 6% 8% 4 4 3 3 4 5% 31%	5465
April	1st to 10th	Day	20% 13% 4 6% 4 5% 4 3 5% 6% 30%	2350
	11th to 20th	Day	21% 11% 3 6% 5% 4 4 3 4 5% 36%	2395
	21st to end	Day	22% 10% 3 6% 5% 3 3 3 4 5% 35%	2470
May	1st to 10th	Day	19% 7% 2 7% 4 5% 5% 4 5% 7% 34%	4135
	11th to 20th	Day	13% 8% 3 7% 4 3 4 3 6% 8% 41%	4398
	21st to end	Day	18% 6% 2 5% 3 3 4 3 5% 7% 43%	4837
June	1st to 10th	Day	17% 8% 3 7% 4 4 4 4 5% 8% 37%	2748
	11th to 20th	Day	13% 6% 2 6% 5% 5% 4 4 6% 9% 40%	2850
	21st to end	Day	18% 8% 2 7% 5% 4 4 5% 5% 8% 35%	2850
July	1st to 10th	Day	16% 6% 2 7% 4 4 5% 4 6% 8% 37%	4760
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 4 5% 8% 45%	4664
	21st to end	Day	10% 6% 2 5% 4 4 4 3 5% 7% 50%	4593
August	1st to 10th	Day	11% 7% 3 6% 5% 5% 5% 4 7% 8% 39%	4104
	11th to 20th	Day	16% 6% 2 6% 3 5% 5% 4 6% 9% 38%	4044
	21st to end	Day	9% 5% 2 6% 5% 4 5% 4 6% 9% 46%	4441
September	1st to 10th	Day	14% 6% 3 6% 3 4 5% 4 6% 7% 42%	2280
	11th to 20th	Day	15% 7% 2 5% 4 3 4 3 5% 7% 46%	2142
	21st to end	Day	20% 7% 3 7% 4 5% 4 3 5% 6% 36%	2068
October	1st to 10th	Day	21% 8% 2 7% 5% 3 5% 4 5% 6% 34%	1900
	11th to 20th	Day	27% 12% 3 8% 4 5% 5% 3 5% 5% 25%	1900
	21st to end	Day	31% 13% 4 8% 4 3 4 3 5% 4 22%	2059
November	1st to 10th	Day	21% 14% 4 9% 5% 4 4 4 4 8% 25%	1626
	11th to 20th	Day	21% 15% 5% 9% 5% 5% 5% 3 5% 6% 22%	1600
	21st to end	Day	22% 22% 4 8% 6% 4 4 3 4 5% 17%	1600
December	1st to 10th	Day	16% 25% 6% 10% 5% 4 5% 3 5% 6% 15%	2600
	11th to 20th	Day	21% 22% 6% 13% 5% 4 3 2 2 4 19%	2959
	21st to end	Day	26% 18% 7% 12% 4 3 3 2 3 4 17%	3476
January	1st to 10th	Night	13% 17% 10% 13% 6% 4 4 3 4 6% 20%	6808
	11th to 20th	Night	12% 17% 7% 19% 6% 5% 5% 3 4 5% 14%	6239
	21st to end	Night	12% 19% 9% 16% 7% 5% 4 3 4 4 17%	6490
February	1st to 10th	Night	13% 19% 6% 12% 7% 5% 4 4 5% 6% 20%	2600
	11th to 20th	Night	12% 15% 7% 12% 6% 5% 4 3 5% 5% 25%	2533
	21st to end	Night	15% 17% 6% 11% 6% 5% 5% 4 4 4 23%	2095
March	1st to 10th	Night	17% 13% 4 8% 5% 4 4 3 5% 6% 31%	4957
	11th to 20th	Night	12% 14% 5% 9% 5% 5% 4 4 5% 7% 29%	4979
	21st to end	Night	22% 11% 4 7% 4 4 3 3 4 5% 33%	5467
April	1st to 10th	Night	21% 12% 4 7% 4 4 4 3 5% 6% 31%	2050
	11th to 20th	Night	19% 10% 3 7% 4 3 4 4 5% 6% 35%	1756
	21st to end	Night	21% 10% 2 8% 4 6% 5% 3 5% 6% 31%	1710
May	1st to 10th	Night	16% 7% 3 7% 5% 4 5% 4 6% 8% 36%	2806
	11th to 20th	Night	13% 7% 2 7% 5% 4 4 4 6% 8% 40%	2495
	21st to end	Night	12% 7% 2 7% 4 4 5% 4 6% 8% 42%	2738
June	1st to 10th	Night	16% 7% 3 7% 4 4 4 4 5% 8% 38%	1427
	11th to 20th	Night	12% 7% 1 4 3 4 4 4 6% 9% 44%	1330
	21st to end	Night	15% 7% 3 5% 3 4 4 4 7% 7% 41%	1330
July	1st to 10th	Night	11% 7% 3 7% 3 4 4 3 5% 7% 47%	2210
	11th to 20th	Night	15% 6% 1 5% 3 3 3 3 5% 7% 48%	2300
	21st to end	Night	9% 6% 2 5% 3 3 4 4 5% 7% 51%	2956
August	1st to 10th	Night	11% 7% 2 6% 3 4 4 3 6% 8% 45%	2825
	11th to 20th	Night	15% 7% 2 6% 4 4 4 3 5% 7% 43%	2785
	21st to end	Night	14% 5% 2 4 3 3 4 3 5% 7% 50%	3183
September	1st to 10th	Night	11% 5% 1 6% 4 4 4 4 5% 8% 47%	1900
	11th to 20th	Night	12% 5% 2 5% 4 3 4 3 5% 7% 50%	2033
	21st to end	Night	18% 6% 2 6% 4 5% 4 3 5% 6% 41%	2111
October	1st to 10th	Night	22% 8% 3 7% 4 4 3 3 5% 5% 36%	2280
	11th to 20th	Night	25% 10% 3 9% 5% 5% 4 3 4 5% 25%	2280
	21st to end	Night	27% 11% 4 10% 4 3 4 3 4 5% 25%	2536
November	1st to 10th	Night	23% 12% 3 8% 4 4 4 3 4 7% 29%	2670
	11th to 20th	Night	19% 16% 4 9% 5% 4 4 3 5% 6% 24%	2800
	21st to end	Night	24% 20% 4 9% 6% 5% 3 3 5% 5% 16%	2800
December	1st to 10th	Night	18% 25% 6% 10% 5% 4 4 3 5% 6% 14%	4580
	11th to 20th	Night	19% 21% 7% 16% 6% 5% 3 3 3 3 14%	5231
	21st to end	Night	22% 21% 5% 13% 5% 4 3 3 3 4 16%	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	62% 4 7% 19% 8%	3159
	11th to 20th	Day	76% 3 6% 9% 5% 1	3667
	21st to end	Day	72% 5% 6% 10% 7% 1	4466
February	1st to 10th	Day	68% 4 7% 16% 4 1	1800
	11th to 20th	Day	60% 5% 10% 14% 9% 1	1762
	21st to end	Day	65% 5% 7% 17% 6%	1530
March	1st to 10th	Day	59% 6% 10% 9% 14% 2	4885
	11th to 20th	Day	56% 5% 13% 17% 8% 2	4980
	21st to end	Day	54% 7% 8% 19% 11% 2	5465
April	1st to 10th	Day	55% 5% 9% 18% 10% 1	2350
	11th to 20th	Day	51% 5% 7% 22% 14% 1	2395
	21st to end	Day	51% 6% 9% 18% 14% 3	2470
May	1st to 10th	Day	45% 10% 7% 24% 12% 2	4147
	11th to 20th	Day	40% 8% 12% 29% 10% 1	4402
	21st to end	Day	41% 6% 13% 20% 17% 3	4837
June	1st to 10th	Day	45% 7% 9% 25% 13% 1	2748
	11th to 20th	Day	41% 6% 10% 25% 17% 1	2850
	21st to end	Day	46% 7% 12% 21% 11% 1	2850
July	1st to 10th	Day	45% 5% 15% 24% 10% 1	4686
	11th to 20th	Day	39% 4 14% 32% 10%	4583
	21st to end	Day	34% 4 11% 31% 19% 1	4447
August	1st to 10th	Day	43% 5% 12% 28% 11% 1	4091
	11th to 20th	Day	43% 5% 15% 27% 10%	4083
	21st to end	Day	36% 5% 11% 37% 11%	4441
September	1st to 10th	Day	40% 7% 12% 29% 11% 1	2280
	11th to 20th	Day	37% 6% 14% 30% 12%	2142
	21st to end	Day	49% 6% 11% 24% 9%	2068
October	1st to 10th	Day	46% 4 12% 25% 13%	3160
	11th to 20th	Day	51% 5% 14% 25% 6%	3140
	21st to end	Day	61% 3 13% 16% 6%	3373
November	1st to 10th	Day	58% 6% 12% 19% 5%	1626
	11th to 20th	Day	64% 5% 12% 13% 6% 1	1600
	21st to end	Day	70% 5% 12% 9% 3 1	1600
December	1st to 10th	Day	72% 3 14% 8% 2	2600
	11th to 20th	Day	72% 2 7% 13% 5%	2959
	21st to end	Day	73% 4 5% 12% 6%	3476
January	1st to 10th	Night	68% 4 6% 15% 7%	6808
	11th to 20th	Night	74% 4 7% 8% 7%	6281
	21st to end	Night	72% 3 6% 9% 8% 1	6490
February	1st to 10th	Night	65% 5% 9% 15% 5% 1	2600
	11th to 20th	Night	62% 5% 10% 16% 7% 1	2535
	21st to end	Night	64% 5% 9% 15% 7% 1	2095
March	1st to 10th	Night	54% 5% 11% 13% 13% 4	4967
	11th to 20th	Night	54% 4 16% 17% 8% 1	4980
	21st to end	Night	55% 4 7% 20% 13% 2	5467
April	1st to 10th	Night	54% 4 7% 21% 12% 2	2050
	11th to 20th	Night	50% 5% 6% 21% 16% 1	1756
	21st to end	Night	54% 4 9% 15% 16% 2	1710
May	1st to 10th	Night	43% 7% 11% 25% 11% 2	2813
	11th to 20th	Night	40% 6% 11% 26% 16% 1	2496
	21st to end	Night	38% 7% 12% 24% 17% 3	2739
June	1st to 10th	Night	45% 6% 10% 23% 14% 2	1427
	11th to 20th	Night	36% 5% 12% 27% 19%	1330
	21st to end	Night	40% 5% 14% 26% 13% 1	1330
July	1st to 10th	Night	38% 3 14% 26% 16% 3	2175
	11th to 20th	Night	37% 3 12% 37% 11% 1	2258
	21st to end	Night	34% 4 9% 31% 22% 1	2862
August	1st to 10th	Night	37% 4 18% 24% 16% 2	2814
	11th to 20th	Night	41% 4 18% 25% 11% 1	2812
	21st to end	Night	35% 3 11% 37% 14% 1	3183
September	1st to 10th	Night	35% 6% 16% 28% 15% 1	1900
	11th to 20th	Night	33% 7% 15% 32% 12%	2033
	21st to end	Night	44% 5% 14% 26% 11%	2111
October	1st to 10th	Night	41% 3 9% 30% 17%	3800
	11th to 20th	Night	51% 3 15% 25% 6%	3779
	21st to end	Night	57% 3 17% 17% 6%	4172
November	1st to 10th	Night	56% 5% 13% 20% 6%	2670
	11th to 20th	Night	61% 5% 15% 13% 6% 1	2800
	21st to end	Night	70% 5% 12% 10% 3	2800
December	1st to 10th	Night	73% 3 13% 8% 3	4580
	11th to 20th	Night	76% 4 6% 9% 5%	5231
	21st to end	Night	74% 3 6% 11% 5%	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	24% 22% 37% 11% 5% 2	200
	11th to 20th	Day	24% 18% 36% 17% 3 1	253
	21st to end	Day	32% 12% 36% 14% 6%	330
February	1st to 10th	Day	34% 20% 35% 8% 3 1	300
	11th to 20th	Day	23% 24% 40% 12% 1	300
	21st to end	Day	36% 22% 34% 7%	249
March	1st to 10th	Day	28% 18% 35% 16% 3	474
	11th to 20th	Day	24% 18% 39% 14% 5% 1	500
	21st to end	Day	30% 17% 31% 17% 5% 1	550
April	1st to 10th	Day	28% 18% 30% 17% 6%	500
	11th to 20th	Day	34% 16% 24% 15% 8% 3	452
	21st to end	Day	30% 15% 33% 15% 6% 1	460
May	1st to 10th	Day	26% 10% 33% 21% 8% 2	463
	11th to 20th	Day	22% 14% 30% 22% 9% 3	487
	21st to end	Day	18% 14% 32% 22% 13% 2	529
June	1st to 10th	Day	21% 12% 30% 27% 7% 2	578
	11th to 20th	Day	17% 10% 35% 26% 10% 2	680
	21st to end	Day	21% 9% 35% 24% 9% 1	680
July	1st to 10th	Day	13% 6% 35% 30% 14% 2	671
	11th to 20th	Day	13% 8% 30% 31% 13% 4	611
	21st to end	Day	13% 6% 34% 30% 12% 5%	532
August	1st to 10th	Day	15% 9% 24% 32% 14% 5%	486
	11th to 20th	Day	17% 4 25% 29% 16% 9%	479
	21st to end	Day	17% 10% 28% 26% 15% 5%	539
September	1st to 10th	Day	15% 10% 31% 26% 13% 5%	490
	11th to 20th	Day	16% 6% 25% 27% 20% 7%	490
	21st to end	Day	21% 9% 24% 28% 16% 3	490
October	1st to 10th	Day	27% 13% 26% 20% 13% 2	490
	11th to 20th	Day	29% 14% 35% 17% 4 2	490
	21st to end	Day	38% 15% 30% 14% 2 1	508
November	1st to 10th	Day	36% 16% 31% 13% 3	231
	11th to 20th	Day	26% 23% 35% 15% 2	200
	21st to end	Day	34% 20% 32% 11% 3 1	200
December	1st to 10th	Day	30% 19% 33% 15% 4	200
	11th to 20th	Day	35% 20% 29% 14% 2 1	200
	21st to end	Day	37% 19% 30% 10% 4	220
January	1st to 10th	Night	28% 14% 33% 21% 3 1	1000
	11th to 20th	Night	31% 14% 31% 19% 5%	878
	21st to end	Night	22% 10% 37% 23% 8% 1	880
February	1st to 10th	Night	23% 18% 34% 22% 3	800
	11th to 20th	Night	22% 14% 36% 21% 7%	783
	21st to end	Night	25% 16% 32% 23% 4	660
March	1st to 10th	Night	21% 16% 35% 24% 5%	800
	11th to 20th	Night	22% 12% 37% 24% 4 1	800
	21st to end	Night	21% 10% 33% 26% 8% 1	880
April	1st to 10th	Night	27% 12% 31% 25% 5%	800
	11th to 20th	Night	25% 12% 29% 24% 10% 1	628
	21st to end	Night	26% 10% 27% 25% 11%	570
May	1st to 10th	Night	21% 5% 26% 34% 12% 2	556
	11th to 20th	Night	17% 6% 27% 37% 11% 1	374
	21st to end	Night	13% 6% 31% 35% 14%	411
June	1st to 10th	Night	17% 4 29% 36% 12% 1	380
	11th to 20th	Night	18% 7% 23% 37% 15%	380
	21st to end	Night	17% 6% 24% 34% 17% 2	380
July	1st to 10th	Night	11% 3 18% 46% 20% 2	370
	11th to 20th	Night	13% 3 24% 37% 22% 1	368
	21st to end	Night	14% 4 22% 35% 23% 1	545
August	1st to 10th	Night	14% 3 19% 35% 26% 3	567
	11th to 20th	Night	14% 2 19% 34% 26% 5%	564
	21st to end	Night	18% 6% 20% 32% 22% 3	660
September	1st to 10th	Night	14% 5% 27% 30% 19% 4	760
	11th to 20th	Night	15% 6% 22% 31% 22% 4	760
	21st to end	Night	22% 7% 21% 31% 17% 4	760
October	1st to 10th	Night	25% 10% 27% 25% 12% 1	760
	11th to 20th	Night	32% 10% 26% 23% 8% 1	760
	21st to end	Night	33% 13% 30% 22% 3	836
November	1st to 10th	Night	33% 7% 29% 21% 8% 1	780
	11th to 20th	Night	29% 15% 29% 22% 5%	800
	21st to end	Night	38% 12% 26% 20% 4	800
December	1st to 10th	Night	34% 15% 30% 16% 5%	800
	11th to 20th	Night	31% 17% 33% 16% 3 1	810
	21st to end	Night	33% 14% 30% 18% 4	1100

Page generated at 2025-04-08 09:17:26. Version ac07

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