Timmins
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Timmins clear sky chart from 2005-11-06 to 2025-10-19.

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% 12% 4 9% 5% 5% 5% 4 5% 6% 28%	127012
	Night	15% 15% 5% 11% 6% 5% 5% 3 4 5% 24%	122876
Transparency	Day	57% 5% 11% 18% 8% 1	130437
	Night	62% 4 9% 17% 7% 1	127538
Seeing	Day	24% 15% 32% 20% 7% 2	16648
	Night	24% 12% 31% 24% 8% 1	25643

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	9% 21% 10% 22% 8% 7% 6% 3 4 3 8%	3158
	11th to 20th	Day	6% 17% 8% 18% 8% 6% 6% 4 7% 5% 15%	3193
	21st to end	Day	8% 18% 10% 15% 6% 8% 8% 4 6% 5% 13%	4009
February	1st to 10th	Day	6% 13% 6% 13% 10% 9% 8% 3 5% 7% 19%	1800
	11th to 20th	Day	9% 19% 7% 10% 7% 6% 7% 6% 5% 7% 18%	1753
	21st to end	Day	10% 18% 6% 11% 6% 8% 6% 4 5% 5% 21%	1547
March	1st to 10th	Day	13% 17% 5% 10% 7% 5% 5% 5% 6% 5% 23%	4696
	11th to 20th	Day	16% 17% 6% 11% 9% 6% 3 3 4 5% 21%	4980
	21st to end	Day	14% 17% 5% 12% 6% 6% 5% 3 4 4 25%	5465
April	1st to 10th	Day	18% 17% 5% 10% 6% 4 4 3 5% 5% 23%	2410
	11th to 20th	Day	19% 14% 3 8% 5% 5% 4 3 4 6% 29%	2572
	21st to end	Day	20% 12% 4 8% 4 4 4 3 4 5% 32%	2600
May	1st to 10th	Day	16% 12% 4 7% 4 4 3 3 4 5% 39%	6062
	11th to 20th	Day	13% 9% 3 8% 5% 5% 5% 4 6% 7% 36%	6356
	21st to end	Day	21% 10% 2 6% 4 4 4 3 4 6% 36%	7451
June	1st to 10th	Day	20% 9% 3 7% 4 5% 5% 4 6% 7% 30%	3000
	11th to 20th	Day	17% 8% 2 6% 4 5% 4 4 5% 8% 36%	3000
	21st to end	Day	22% 8% 3 7% 5% 5% 5% 3 5% 7% 31%	3000
July	1st to 10th	Day	16% 7% 3 6% 5% 5% 5% 5% 8% 10% 30%	6819
	11th to 20th	Day	16% 7% 2 6% 4 5% 5% 5% 7% 9% 34%	6820
	21st to end	Day	17% 7% 2 6% 4 4 5% 4 7% 8% 35%	7299
August	1st to 10th	Day	12% 6% 2 7% 5% 5% 5% 5% 7% 8% 38%	4239
	11th to 20th	Day	17% 8% 3 7% 4 4 5% 4 5% 7% 37%	4174
	21st to end	Day	17% 6% 2 6% 4 5% 5% 4 5% 8% 37%	4675
September	1st to 10th	Day	20% 8% 3 7% 5% 4 4 3 5% 7% 34%	2440
	11th to 20th	Day	22% 9% 2 7% 4 4 3 3 5% 7% 34%	2207
	21st to end	Day	23% 11% 3 7% 4 3 3 3 4 6% 33%	2200
October	1st to 10th	Day	23% 14% 4 6% 3 4 3 3 4 6% 31%	2015
	11th to 20th	Day	27% 18% 4 8% 4 5% 4 2 3 4 20%	1980
	21st to end	Day	25% 23% 6% 11% 5% 4 3 3 3 4 13%	1914
November	1st to 10th	Day	22% 20% 7% 11% 5% 4 3 3 4 4 18%	1596
	11th to 20th	Day	18% 23% 8% 15% 7% 5% 3 3 3 4 11%	1600
	21st to end	Day	20% 24% 6% 16% 7% 5% 4 3 3 3 9%	1600
December	1st to 10th	Day	14% 19% 12% 25% 9% 4 3 2 3 2 7%	2285
	11th to 20th	Day	12% 19% 5% 14% 8% 8% 5% 3 4 4 17%	2621
	21st to end	Day	18% 21% 9% 14% 7% 4 4 3 5% 4 9%	3476
January	1st to 10th	Night	9% 20% 10% 19% 9% 8% 6% 3 4 3 10%	6808
	11th to 20th	Night	9% 17% 7% 17% 9% 6% 7% 6% 7% 5% 10%	6708
	21st to end	Night	7% 18% 10% 15% 7% 6% 7% 4 5% 5% 17%	6953
February	1st to 10th	Night	8% 14% 5% 12% 11% 8% 6% 5% 6% 6% 19%	2600
	11th to 20th	Night	9% 17% 6% 14% 9% 6% 5% 4 5% 6% 19%	2533
	21st to end	Night	10% 17% 6% 14% 7% 7% 6% 4 5% 5% 19%	2080
March	1st to 10th	Night	17% 17% 5% 11% 5% 4 5% 3 3 4 25%	5143
	11th to 20th	Night	17% 18% 6% 14% 8% 4 3 2 3 3 21%	4979
	21st to end	Night	14% 15% 6% 12% 6% 6% 5% 3 4 6% 23%	5467
April	1st to 10th	Night	18% 15% 5% 10% 5% 4 4 4 4 6% 26%	2006
	11th to 20th	Night	19% 11% 4 9% 4 4 5% 3 4 6% 30%	1777
	21st to end	Night	19% 13% 3 8% 4 4 4 3 4 5% 34%	1800
May	1st to 10th	Night	16% 12% 3 7% 5% 4 4 3 5% 5% 37%	3879
	11th to 20th	Night	14% 8% 3 7% 3 5% 4 4 5% 7% 40%	3536
	21st to end	Night	17% 9% 3 5% 4 4 4 3 5% 8% 38%	3447
June	1st to 10th	Night	22% 8% 3 6% 3 4 4 3 5% 8% 32%	1400
	11th to 20th	Night	16% 8% 3 6% 4 5% 5% 3 6% 6% 38%	1400
	21st to end	Night	21% 9% 2 6% 4 4 4 3 6% 8% 35%	1400
July	1st to 10th	Night	17% 8% 2 7% 4 4 3 3 4 7% 40%	3160
	11th to 20th	Night	17% 8% 3 7% 4 4 3 4 6% 7% 38%	3160
	21st to end	Night	15% 7% 2 5% 4 4 4 3 6% 7% 42%	3571
August	1st to 10th	Night	9% 6% 3 8% 6% 5% 6% 4 6% 7% 41%	2909
	11th to 20th	Night	17% 9% 3 7% 4 3 3 3 5% 6% 39%	2875
	21st to end	Night	14% 7% 2 5% 4 4 3 3 4 6% 47%	3223
September	1st to 10th	Night	20% 7% 3 5% 5% 4 4 3 5% 6% 38%	1940
	11th to 20th	Night	20% 11% 2 6% 3 3 3 2 4 6% 40%	2190
	21st to end	Night	22% 9% 3 5% 4 4 3 3 4 5% 38%	2200
October	1st to 10th	Night	21% 11% 3 7% 5% 4 3 3 5% 6% 31%	2385
	11th to 20th	Night	25% 19% 4 8% 5% 3 4 3 3 5% 21%	2377
	21st to end	Night	23% 21% 5% 7% 6% 3 4 3 4 5% 19%	2682
November	1st to 10th	Night	19% 18% 6% 11% 5% 4 5% 3 5% 4 19%	2700
	11th to 20th	Night	22% 19% 7% 14% 6% 5% 4 2 3 4 15%	2800
	21st to end	Night	19% 22% 8% 15% 7% 5% 4 2 3 3 11%	2800
December	1st to 10th	Night	11% 27% 9% 18% 10% 7% 3 3 3 2 7%	4900
	11th to 20th	Night	11% 17% 7% 16% 10% 8% 6% 3 3 4 13%	5586
	21st to end	Night	21% 22% 6% 12% 6% 5% 3 4 4 4 13%	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	82% 2 6% 6% 2 1	3159
	11th to 20th	Day	69% 3 7% 14% 6%	3220
	21st to end	Day	72% 4 6% 14% 4	4009
February	1st to 10th	Day	66% 4 8% 15% 6%	1800
	11th to 20th	Day	64% 4 10% 14% 8%	1762
	21st to end	Day	65% 3 6% 16% 9% 1	1547
March	1st to 10th	Day	63% 4 8% 14% 10% 2	4699
	11th to 20th	Day	67% 4 10% 12% 7%	4980
	21st to end	Day	64% 3 7% 16% 10% 1	5465
April	1st to 10th	Day	63% 4 7% 16% 9% 1	2410
	11th to 20th	Day	56% 4 7% 22% 10% 1	2572
	21st to end	Day	55% 4 9% 17% 13% 2	2600
May	1st to 10th	Day	48% 4 8% 18% 20% 2	6071
	11th to 20th	Day	46% 6% 15% 18% 12% 4	6360
	21st to end	Day	50% 4 9% 20% 14% 3	7451
June	1st to 10th	Day	52% 5% 12% 21% 11%	3000
	11th to 20th	Day	46% 5% 11% 23% 15% 1	3000
	21st to end	Day	53% 5% 12% 20% 9% 1	3000
July	1st to 10th	Day	45% 8% 15% 25% 7%	6746
	11th to 20th	Day	42% 8% 19% 22% 8%	6739
	21st to end	Day	45% 6% 14% 28% 6%	7089
August	1st to 10th	Day	41% 7% 17% 27% 8%	4225
	11th to 20th	Day	46% 7% 14% 27% 6%	4213
	21st to end	Day	43% 6% 15% 28% 6% 2	4674
September	1st to 10th	Day	50% 5% 16% 20% 8% 1	2440
	11th to 20th	Day	51% 6% 16% 22% 6%	2207
	21st to end	Day	53% 5% 12% 21% 8%	2200
October	1st to 10th	Day	55% 4 14% 21% 6%	3275
	11th to 20th	Day	61% 3 11% 19% 6%	3220
	21st to end	Day	72% 3 11% 8% 5%	3126
November	1st to 10th	Day	69% 5% 12% 9% 4	1596
	11th to 20th	Day	79% 3 7% 8% 2	1600
	21st to end	Day	82% 3 8% 6% 1	1600
December	1st to 10th	Day	86% 2 5% 4 2	2285
	11th to 20th	Day	72% 3 11% 11% 2	2621
	21st to end	Day	78% 3 5% 12% 3	3476
January	1st to 10th	Night	81% 2 7% 6% 2	6808
	11th to 20th	Night	73% 3 7% 12% 5%	6756
	21st to end	Night	69% 3 6% 15% 6%	6953
February	1st to 10th	Night	63% 5% 10% 14% 8%	2600
	11th to 20th	Night	65% 3 10% 16% 6%	2535
	21st to end	Night	66% 4 8% 14% 7% 1	2080
March	1st to 10th	Night	64% 3 7% 14% 9% 3	5153
	11th to 20th	Night	70% 3 6% 13% 7% 1	4980
	21st to end	Night	62% 4 6% 15% 10% 2	5467
April	1st to 10th	Night	60% 4 7% 17% 11% 1	2006
	11th to 20th	Night	56% 3 7% 20% 12% 2	1777
	21st to end	Night	53% 4 8% 17% 17% 2	1800
May	1st to 10th	Night	48% 5% 6% 20% 17% 3	3886
	11th to 20th	Night	43% 6% 11% 25% 12% 2	3537
	21st to end	Night	45% 5% 12% 18% 18% 2	3448
June	1st to 10th	Night	50% 5% 11% 19% 14% 2	1400
	11th to 20th	Night	45% 6% 9% 24% 16% 1	1400
	21st to end	Night	47% 4 13% 22% 12% 1	1400
July	1st to 10th	Night	44% 6% 11% 30% 9%	3125
	11th to 20th	Night	44% 6% 14% 28% 7%	3118
	21st to end	Night	41% 6% 16% 30% 7%	3467
August	1st to 10th	Night	39% 7% 16% 33% 5%	2899
	11th to 20th	Night	45% 6% 14% 31% 4	2902
	21st to end	Night	39% 4 12% 33% 10% 1	3223
September	1st to 10th	Night	47% 5% 15% 23% 9%	1940
	11th to 20th	Night	46% 5% 18% 25% 5%	2190
	21st to end	Night	50% 5% 15% 24% 7%	2200
October	1st to 10th	Night	52% 6% 12% 23% 7%	3905
	11th to 20th	Night	61% 5% 10% 19% 5%	3876
	21st to end	Night	64% 6% 14% 11% 5%	4420
November	1st to 10th	Night	68% 6% 11% 12% 3	2700
	11th to 20th	Night	74% 4 9% 10% 3	2800
	21st to end	Night	80% 4 8% 7% 1	2800
December	1st to 10th	Night	85% 4 5% 5% 2	4900
	11th to 20th	Night	75% 4 6% 10% 4	5585
	21st to end	Night	76% 3 6% 11% 4	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	22% 17% 38% 17% 5% 2	200
	11th to 20th	Day	18% 18% 36% 22% 6% 1	211
	21st to end	Day	20% 14% 36% 25% 4 1	330
February	1st to 10th	Day	18% 26% 35% 15% 4 1	300
	11th to 20th	Day	20% 20% 41% 16% 1 2	300
	21st to end	Day	27% 25% 34% 12% 2	249
March	1st to 10th	Day	20% 20% 40% 18% 2	389
	11th to 20th	Day	26% 19% 33% 16% 5% 1	500
	21st to end	Day	25% 21% 31% 17% 5% 1	550
April	1st to 10th	Day	23% 21% 31% 17% 6% 1	500
	11th to 20th	Day	29% 19% 27% 17% 5% 3	492
	21st to end	Day	29% 18% 27% 16% 7% 2	500
May	1st to 10th	Day	23% 14% 34% 19% 7% 2	503
	11th to 20th	Day	21% 16% 33% 20% 8% 2	539
	21st to end	Day	25% 13% 32% 22% 7% 1	789
June	1st to 10th	Day	23% 14% 35% 21% 5% 1	730
	11th to 20th	Day	23% 16% 32% 20% 8% 1	730
	21st to end	Day	25% 11% 28% 24% 10% 2	730
July	1st to 10th	Day	17% 11% 35% 26% 8% 3	721
	11th to 20th	Day	17% 13% 31% 27% 10% 2	718
	21st to end	Day	19% 7% 32% 26% 11% 4	794
August	1st to 10th	Day	15% 13% 31% 26% 12% 4	531
	11th to 20th	Day	19% 8% 25% 26% 16% 6%	519
	21st to end	Day	23% 11% 26% 23% 11% 5%	583
September	1st to 10th	Day	23% 13% 30% 19% 12% 3	530
	11th to 20th	Day	27% 9% 29% 22% 9% 4	530
	21st to end	Day	29% 13% 26% 22% 8% 1	530
October	1st to 10th	Day	30% 15% 28% 20% 6% 2	530
	11th to 20th	Day	34% 19% 30% 13% 3 1	522
	21st to end	Day	33% 21% 31% 12% 2 1	363
November	1st to 10th	Day	39% 16% 31% 13% 1	215
	11th to 20th	Day	36% 21% 29% 12% 3 1	200
	21st to end	Day	35% 22% 31% 11% 2 1	200
December	1st to 10th	Day	24% 17% 38% 15% 7% 1	200
	11th to 20th	Day	24% 19% 39% 12% 5% 2	200
	21st to end	Day	30% 18% 32% 13% 5% 1	220
January	1st to 10th	Night	24% 13% 38% 19% 5% 1	1000
	11th to 20th	Night	22% 13% 32% 25% 7% 1	1000
	21st to end	Night	18% 13% 30% 28% 10% 1	1083
February	1st to 10th	Night	15% 15% 37% 23% 9% 1	800
	11th to 20th	Night	18% 15% 34% 24% 7%	783
	21st to end	Night	19% 17% 38% 20% 6%	660
March	1st to 10th	Night	20% 17% 34% 23% 5% 1	800
	11th to 20th	Night	24% 19% 30% 21% 5% 1	800
	21st to end	Night	22% 12% 37% 21% 7% 1	880
April	1st to 10th	Night	27% 14% 31% 22% 6% 1	731
	11th to 20th	Night	24% 15% 28% 23% 9% 1	593
	21st to end	Night	24% 12% 30% 25% 10% 1	600
May	1st to 10th	Night	22% 8% 33% 32% 6%	530
	11th to 20th	Night	21% 10% 34% 27% 6% 2	394
	21st to end	Night	20% 9% 33% 32% 6%	433
June	1st to 10th	Night	27% 9% 26% 31% 7%	400
	11th to 20th	Night	18% 9% 33% 30% 10% 1	400
	21st to end	Night	22% 8% 27% 33% 11% 1	400
July	1st to 10th	Night	18% 9% 29% 32% 12% 1	390
	11th to 20th	Night	19% 5% 28% 37% 11%	388
	21st to end	Night	16% 7% 26% 35% 14% 2	488
August	1st to 10th	Night	15% 6% 29% 33% 15% 2	597
	11th to 20th	Night	19% 5% 23% 32% 19% 2	594
	21st to end	Night	21% 8% 27% 27% 15% 2	660
September	1st to 10th	Night	23% 9% 28% 25% 14% 1	740
	11th to 20th	Night	27% 8% 26% 25% 13% 1	800
	21st to end	Night	27% 9% 25% 26% 11% 2	800
October	1st to 10th	Night	27% 11% 29% 25% 8% 1	800
	11th to 20th	Night	35% 13% 29% 15% 6% 1	793
	21st to end	Night	34% 13% 29% 18% 5% 1	836
November	1st to 10th	Night	30% 16% 30% 20% 5% 1	780
	11th to 20th	Night	33% 15% 29% 18% 4	800
	21st to end	Night	33% 14% 34% 15% 3 1	800
December	1st to 10th	Night	25% 17% 32% 20% 6% 1	990
	11th to 20th	Night	25% 14% 35% 19% 6% 1	1000
	21st to end	Night	30% 14% 28% 20% 6% 1	1100

Page generated at 2025-10-16 01:50:30. Version ac07

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