Petawawa Terrace Provincial Nature Reserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Petawawa Terrace Provincial Nature Reserve clear sky chart from 2005-11-06 to 2024-01-12.

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 7% 6% 3 5% 5% 5% 6% 32%	74708
	Night	18% 11% 4 8% 6% 3 5% 4 5% 6% 31%	75009
Transparency	Day	52% 6% 11% 19% 10% 1	74413
	Night	54% 6% 11% 19% 10% 1	74838
Seeing	Day	22% 12% 29% 22% 11% 4	13246
	Night	23% 10% 27% 28% 11% 1	22528

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	17% 16% 7% 11% 9% 4 4 4 4 4 20%	1517
	11th to 20th	Day	18% 16% 6% 10% 6% 3 5% 4 4 5% 22%	1454
	21st to end	Day	13% 15% 6% 10% 9% 5% 5% 4 4 5% 25%	1706
February	1st to 10th	Day	12% 15% 7% 12% 8% 5% 7% 5% 5% 5% 20%	1620
	11th to 20th	Day	13% 15% 7% 10% 6% 4 5% 5% 5% 6% 25%	1573
	21st to end	Day	18% 14% 5% 8% 6% 5% 4 5% 5% 7% 23%	1415
March	1st to 10th	Day	15% 13% 6% 9% 7% 3 4 4 4 6% 28%	1867
	11th to 20th	Day	14% 12% 5% 8% 8% 4 6% 5% 4 5% 29%	1980
	21st to end	Day	18% 9% 5% 6% 5% 3 4 3 5% 6% 37%	2240
April	1st to 10th	Day	22% 12% 4 6% 5% 3 5% 4 4 6% 30%	2160
	11th to 20th	Day	21% 9% 3 5% 5% 3 4 4 5% 4 36%	2134
	21st to end	Day	21% 9% 3 6% 6% 3 5% 4 4 6% 32%	2331
May	1st to 10th	Day	18% 9% 3 7% 5% 3 4 4 5% 6% 35%	2514
	11th to 20th	Day	18% 8% 4 6% 6% 3 4 5% 4 6% 36%	2478
	21st to end	Day	14% 7% 3 6% 6% 3 5% 5% 5% 8% 38%	2725
June	1st to 10th	Day	20% 7% 3 7% 6% 4 5% 5% 6% 6% 32%	2520
	11th to 20th	Day	15% 5% 3 5% 5% 3 5% 5% 5% 8% 40%	2520
	21st to end	Day	16% 7% 3 5% 7% 3 6% 5% 6% 8% 33%	2520
July	1st to 10th	Day	12% 5% 2 6% 5% 3 6% 5% 7% 8% 40%	2520
	11th to 20th	Day	11% 5% 3 5% 6% 4 7% 6% 7% 9% 38%	2520
	21st to end	Day	11% 5% 3 6% 6% 4 6% 5% 7% 10% 37%	2744
August	1st to 10th	Day	11% 5% 3 6% 6% 4 7% 6% 6% 8% 37%	2404
	11th to 20th	Day	13% 6% 2 6% 6% 4 5% 5% 6% 8% 39%	2303
	21st to end	Day	14% 7% 3 5% 5% 3 4 6% 6% 10% 37%	2422
September	1st to 10th	Day	14% 6% 3 5% 5% 3 4 5% 7% 8% 41%	2160
	11th to 20th	Day	14% 6% 3 6% 5% 4 4 4 5% 6% 44%	2160
	21st to end	Day	18% 7% 3 7% 6% 3 5% 4 5% 8% 36%	1890
October	1st to 10th	Day	20% 8% 2 6% 6% 4 4 5% 5% 6% 35%	1800
	11th to 20th	Day	24% 11% 4 7% 8% 3 4 4 5% 6% 24%	1800
	21st to end	Day	28% 10% 3 8% 7% 4 4 5% 4 5% 22%	1890
November	1st to 10th	Day	16% 10% 4 6% 6% 3 5% 5% 6% 6% 32%	1583
	11th to 20th	Day	19% 13% 5% 9% 7% 4 5% 4 4 5% 25%	1520
	21st to end	Day	26% 14% 6% 8% 7% 3 5% 4 4 5% 16%	1520
December	1st to 10th	Day	22% 17% 6% 8% 7% 4 5% 4 5% 5% 17%	1520
	11th to 20th	Day	20% 16% 7% 10% 6% 4 4 4 4 5% 20%	1906
	21st to end	Day	27% 18% 6% 14% 4 2 3 3 3 3 18%	2772
January	1st to 10th	Night	17% 19% 7% 11% 7% 4 6% 4 4 4 16%	2649
	11th to 20th	Night	17% 16% 6% 11% 8% 4 5% 5% 3 5% 21%	2546
	21st to end	Night	12% 14% 6% 10% 7% 4 5% 5% 5% 5% 28%	2647
February	1st to 10th	Night	14% 14% 7% 11% 8% 3 6% 5% 5% 6% 21%	2340
	11th to 20th	Night	13% 14% 6% 11% 7% 4 5% 4 4 5% 27%	2273
	21st to end	Night	15% 14% 6% 9% 7% 4 4 4 5% 5% 27%	1840
March	1st to 10th	Night	16% 13% 5% 9% 7% 4 6% 4 4 5% 29%	2078
	11th to 20th	Night	15% 13% 5% 7% 6% 3 4 5% 5% 6% 31%	1979
	21st to end	Night	15% 10% 4 6% 5% 3 4 4 4 6% 39%	2114
April	1st to 10th	Night	20% 11% 4 8% 6% 3 4 4 4 5% 31%	1800
	11th to 20th	Night	21% 9% 4 6% 5% 3 4 3 4 5% 36%	1775
	21st to end	Night	21% 10% 3 6% 6% 3 5% 3 3 6% 31%	1643
May	1st to 10th	Night	18% 7% 4 7% 5% 3 4 3 5% 6% 37%	1445
	11th to 20th	Night	20% 7% 2 4 5% 3 4 4 5% 6% 40%	1415
	21st to end	Night	13% 5% 2 5% 6% 2 5% 5% 6% 7% 45%	1550
June	1st to 10th	Night	17% 7% 3 6% 6% 3 5% 5% 6% 7% 36%	1440
	11th to 20th	Night	15% 5% 2 4 6% 3 5% 4 7% 8% 41%	1440
	21st to end	Night	17% 7% 2 5% 5% 3 4 5% 6% 8% 37%	1440
July	1st to 10th	Night	10% 4 2 5% 5% 4 5% 5% 7% 7% 46%	1440
	11th to 20th	Night	13% 5% 3 4 5% 4 4 6% 7% 8% 43%	1440
	21st to end	Night	10% 4 2 5% 6% 4 5% 5% 7% 8% 44%	1574
August	1st to 10th	Night	11% 5% 3 6% 5% 3 6% 4 6% 8% 44%	1531
	11th to 20th	Night	10% 5% 2 5% 5% 4 4 5% 7% 8% 46%	1598
	21st to end	Night	12% 7% 3 5% 5% 3 5% 6% 6% 8% 43%	1916
September	1st to 10th	Night	11% 6% 3 6% 6% 3 4 4 4 8% 45%	1800
	11th to 20th	Night	15% 6% 3 5% 4 2 4 4 5% 6% 47%	1800
	21st to end	Night	19% 7% 2 5% 5% 2 4 4 5% 6% 41%	2066
October	1st to 10th	Night	22% 7% 3 5% 5% 3 4 3 4 6% 38%	2160
	11th to 20th	Night	22% 11% 3 6% 7% 3 5% 4 5% 5% 29%	2160
	21st to end	Night	24% 13% 4 6% 7% 4 4 4 4 6% 25%	2466
November	1st to 10th	Night	19% 11% 3 7% 5% 4 4 5% 4 6% 32%	2492
	11th to 20th	Night	18% 12% 6% 7% 8% 4 5% 5% 5% 6% 26%	2660
	21st to end	Night	23% 15% 6% 10% 6% 3 5% 4 4 5% 20%	2660
December	1st to 10th	Night	22% 19% 7% 10% 6% 3 5% 4 4 5% 16%	2660
	11th to 20th	Night	20% 18% 6% 8% 6% 3 4 4 4 5% 22%	3288
	21st to end	Night	28% 19% 5% 12% 5% 3 3 3 3 4 16%	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	68% 5% 8% 14% 5%	1518
	11th to 20th	Day	66% 5% 8% 11% 9% 1	1454
	21st to end	Day	63% 4 9% 14% 10% 1	1706
February	1st to 10th	Day	66% 4 8% 16% 5% 1	1620
	11th to 20th	Day	59% 5% 13% 13% 9% 1	1582
	21st to end	Day	61% 5% 8% 15% 10% 1	1415
March	1st to 10th	Day	58% 4 10% 17% 10% 1	1870
	11th to 20th	Day	57% 5% 10% 16% 11% 2	1980
	21st to end	Day	50% 3 9% 20% 13% 5%	2240
April	1st to 10th	Day	56% 4 8% 18% 11% 3	2160
	11th to 20th	Day	51% 4 7% 22% 14% 2	2134
	21st to end	Day	53% 5% 7% 15% 16% 3	2331
May	1st to 10th	Day	49% 6% 8% 19% 13% 5%	2514
	11th to 20th	Day	49% 5% 7% 20% 17% 2	2482
	21st to end	Day	44% 6% 12% 20% 13% 4	2725
June	1st to 10th	Day	51% 7% 10% 20% 12% 1	2520
	11th to 20th	Day	42% 7% 11% 23% 14% 3	2520
	21st to end	Day	47% 8% 11% 20% 12% 1	2520
July	1st to 10th	Day	38% 8% 11% 27% 15% 1	2450
	11th to 20th	Day	39% 8% 14% 25% 13% 1	2445
	21st to end	Day	41% 8% 14% 28% 9%	2591
August	1st to 10th	Day	43% 8% 15% 22% 12%	2390
	11th to 20th	Day	42% 8% 17% 25% 8% 1	2303
	21st to end	Day	42% 8% 15% 24% 11% 1	2422
September	1st to 10th	Day	39% 6% 16% 26% 12%	2160
	11th to 20th	Day	40% 7% 11% 31% 10% 1	2160
	21st to end	Day	48% 7% 13% 24% 8%	1890
October	1st to 10th	Day	51% 7% 10% 20% 11% 1	1800
	11th to 20th	Day	61% 6% 14% 15% 4 1	1800
	21st to end	Day	63% 5% 12% 15% 5% 1	1890
November	1st to 10th	Day	50% 7% 14% 23% 7%	1583
	11th to 20th	Day	60% 7% 13% 13% 6% 1	1520
	21st to end	Day	70% 7% 10% 8% 5%	1520
December	1st to 10th	Day	71% 6% 9% 10% 4	1520
	11th to 20th	Day	65% 8% 7% 12% 7%	1906
	21st to end	Day	74% 3 7% 13% 3	2772
January	1st to 10th	Night	71% 6% 9% 10% 4	2649
	11th to 20th	Night	67% 5% 10% 12% 6% 1	2546
	21st to end	Night	58% 5% 9% 17% 11%	2647
February	1st to 10th	Night	65% 6% 9% 14% 6% 1	2340
	11th to 20th	Night	60% 4 11% 18% 7% 1	2275
	21st to end	Night	58% 5% 8% 19% 8% 1	1840
March	1st to 10th	Night	58% 5% 9% 17% 10% 2	2088
	11th to 20th	Night	53% 4 11% 18% 13% 1	1980
	21st to end	Night	48% 5% 8% 20% 15% 4	2114
April	1st to 10th	Night	55% 5% 8% 17% 12% 2	1800
	11th to 20th	Night	50% 4 8% 22% 14% 2	1775
	21st to end	Night	54% 5% 7% 15% 16% 3	1643
May	1st to 10th	Night	47% 4 8% 20% 17% 4	1445
	11th to 20th	Night	45% 5% 8% 22% 17% 3	1416
	21st to end	Night	37% 8% 14% 21% 17% 4	1551
June	1st to 10th	Night	46% 8% 12% 23% 10% 1	1440
	11th to 20th	Night	38% 9% 11% 24% 16% 2	1440
	21st to end	Night	44% 7% 14% 20% 13% 1	1440
July	1st to 10th	Night	33% 9% 13% 25% 19% 2	1400
	11th to 20th	Night	37% 8% 14% 27% 14% 1	1392
	21st to end	Night	36% 8% 16% 29% 11%	1486
August	1st to 10th	Night	38% 7% 17% 25% 13%	1521
	11th to 20th	Night	33% 9% 18% 28% 11% 1	1598
	21st to end	Night	38% 8% 15% 27% 11% 1	1916
September	1st to 10th	Night	38% 7% 12% 29% 14% 1	1800
	11th to 20th	Night	37% 6% 16% 32% 9%	1800
	21st to end	Night	43% 7% 13% 28% 9%	2066
October	1st to 10th	Night	48% 6% 11% 22% 13%	2160
	11th to 20th	Night	57% 6% 12% 19% 6%	2160
	21st to end	Night	60% 6% 11% 16% 7%	2466
November	1st to 10th	Night	53% 6% 14% 19% 8%	2492
	11th to 20th	Night	59% 7% 12% 14% 7% 1	2660
	21st to end	Night	65% 7% 11% 13% 3	2660
December	1st to 10th	Night	71% 5% 9% 11% 4	2660
	11th to 20th	Night	64% 5% 10% 14% 7%	3288
	21st to end	Night	74% 4 7% 11% 4	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	24% 14% 32% 24% 6% 1	180
	11th to 20th	Day	28% 13% 33% 20% 4 2	164
	21st to end	Day	23% 14% 34% 19% 9% 1	230
February	1st to 10th	Day	29% 20% 35% 12% 3 1	240
	11th to 20th	Day	26% 20% 38% 16% 1	240
	21st to end	Day	30% 18% 30% 20% 1	281
March	1st to 10th	Day	23% 16% 34% 23% 3	420
	11th to 20th	Day	24% 16% 30% 23% 6% 1	420
	21st to end	Day	30% 15% 29% 18% 7% 1	462
April	1st to 10th	Day	27% 16% 31% 14% 10% 1	420
	11th to 20th	Day	31% 14% 21% 19% 11% 4	412
	21st to end	Day	28% 13% 33% 15% 8% 2	420
May	1st to 10th	Day	26% 12% 26% 25% 8% 3	423
	11th to 20th	Day	20% 16% 28% 21% 11% 4	447
	21st to end	Day	17% 11% 34% 22% 12% 4	485
June	1st to 10th	Day	24% 9% 34% 20% 11% 1	450
	11th to 20th	Day	18% 11% 27% 26% 13% 6%	450
	21st to end	Day	17% 11% 31% 24% 13% 4	450
July	1st to 10th	Day	11% 6% 26% 39% 14% 4	445
	11th to 20th	Day	15% 7% 27% 31% 17% 5%	444
	21st to end	Day	11% 8% 30% 30% 16% 5%	488
August	1st to 10th	Day	13% 7% 27% 30% 18% 7%	446
	11th to 20th	Day	14% 5% 22% 30% 21% 9%	439
	21st to end	Day	16% 9% 27% 22% 18% 8%	495
September	1st to 10th	Day	13% 7% 29% 24% 18% 9%	450
	11th to 20th	Day	15% 8% 26% 23% 18% 10%	450
	21st to end	Day	16% 12% 28% 22% 17% 6%	450
October	1st to 10th	Day	24% 12% 23% 20% 16% 5%	450
	11th to 20th	Day	27% 18% 29% 16% 7% 2	450
	21st to end	Day	31% 15% 25% 21% 8% 1	450
November	1st to 10th	Day	24% 14% 31% 20% 10%	277
	11th to 20th	Day	26% 17% 36% 13% 6% 2	180
	21st to end	Day	33% 19% 30% 12% 3 3	180
December	1st to 10th	Day	29% 11% 34% 17% 8% 1	180
	11th to 20th	Day	29% 18% 33% 14% 4 2	180
	21st to end	Day	32% 16% 30% 16% 4 2	198
January	1st to 10th	Night	28% 11% 32% 24% 5%	760
	11th to 20th	Night	29% 11% 25% 26% 8% 1	728
	21st to end	Night	20% 9% 31% 31% 9% 1	792
February	1st to 10th	Night	22% 12% 36% 24% 6% 1	720
	11th to 20th	Night	23% 12% 33% 25% 6%	703
	21st to end	Night	21% 16% 29% 28% 6%	592
March	1st to 10th	Night	22% 15% 31% 27% 5%	720
	11th to 20th	Night	22% 15% 30% 25% 7% 1	720
	21st to end	Night	21% 11% 31% 27% 10%	792
April	1st to 10th	Night	28% 12% 27% 27% 6%	720
	11th to 20th	Night	26% 11% 28% 26% 9%	711
	21st to end	Night	25% 10% 26% 26% 12% 1	563
May	1st to 10th	Night	21% 6% 28% 33% 11% 1	365
	11th to 20th	Night	22% 8% 28% 32% 10% 1	354
	21st to end	Night	15% 5% 34% 33% 13%	389
June	1st to 10th	Night	17% 4 31% 40% 6% 1	360
	11th to 20th	Night	16% 7% 25% 34% 18% 1	360
	21st to end	Night	19% 6% 22% 36% 16% 1	360
July	1st to 10th	Night	9% 5% 26% 41% 18% 1	350
	11th to 20th	Night	12% 3 22% 42% 20% 1	348
	21st to end	Night	9% 4 22% 43% 20% 1	394
August	1st to 10th	Night	10% 4 20% 38% 28% 1	457
	11th to 20th	Night	11% 2 16% 37% 30% 4	534
	21st to end	Night	13% 5% 24% 35% 20% 3	728
September	1st to 10th	Night	13% 5% 28% 30% 22% 2	720
	11th to 20th	Night	19% 5% 20% 30% 23% 3	720
	21st to end	Night	22% 7% 21% 28% 20% 2	720
October	1st to 10th	Night	24% 7% 29% 25% 14% 2	720
	11th to 20th	Night	30% 8% 28% 23% 10% 1	720
	21st to end	Night	31% 10% 27% 27% 5% 1	792
November	1st to 10th	Night	25% 12% 25% 28% 10% 1	740
	11th to 20th	Night	25% 14% 32% 20% 9% 1	760
	21st to end	Night	32% 14% 24% 23% 6%	760
December	1st to 10th	Night	32% 14% 30% 18% 6%	760
	11th to 20th	Night	27% 12% 31% 23% 6%	760
	21st to end	Night	34% 13% 25% 22% 5%	836

Page generated at 2024-01-09 16:24:22. Version ac07

Copyright 2024 Attilla Danko